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THE  LIBRARY 

OF 

THE  UNIVERSITY 
OF  CALIFORNIA 

LOS  ANGELES 

GIFT  OF 


John  S.Preli 


ES. 


Work. 


etc.  Tools 
i  Painting, 
g  a  Room. 


and  Shoes. 

sewing  and 

ted  Boots 

Engravings 

The  S'gn- 
he  Simpler 
Signboard. 


ng  Wood. 
i  Spiriting 
e-polishing 
ors  Stains. 


Diagrams 
lanchester 
Wire  for 
sir  Causes 
rmine  the 
ire  Motor. 


. 

ng.     Tyres  and  Methods 


and 

Pioc< 

Dyn 

Dyn; 

Smal 

and 

Dim 

Unde 

Diagrams. 

C<  ront  Driver. 

Buildmg-a— rcear-Kinving  saiety.  Building  landem  Safeties.  Building  Front- 
driver  Tricycle.  Building  a  Hand  Tricycle.  Brazing.  How  to  Make  and  Fit 
Gear  Cases.  Fittings  and  Accessories.  Wheel  Making.  ' 
of  Fixing  them.  Enamelling.  Repairing. 
Decorative  Designs  of  All  Ages  for  All  Purposes.  With  277 
Engravings  and  Diagrams. 

Contents. — Savage  Ornament.  Egyotinn  Ornament.  Assyrian  Ornament 
Greek  Ornament.  Roman  Ornament.  Early  Christian  Ornament.  Arabic 
Ornament.  Celtic  and  Scandinavian  Ornaments.  Mediaeval  Ornament. 
Renascence  and  Modern  Ornaments.  Chinese  Ornament.  Persian  Ornament. 
Indian  Ornament.  Japanese  Ornament. 
Mounting  and  Framing  Pictures.  Wi'h  240  Engravings,  etc. 

Contents. — Making  Picture  Frames.     Notes  on  Art  Frames      Picture  Frame 
Cramps.      Making   Oxford    Frames.      Gilding    Picture    Frames.     Methods  of 
Mounting  Pictures.     Making  Photograph  Frames.     Frames  covered  with  Plush 
and  Cork.     Hanging  and  Packing  Pictures. 
Smiths'  Work.     With  211  Engravings  and  Diagrams. 

Contents.  —  Forges  and  Appliances.  Hand  Tools.  Drawing  Down  and  Up- 
setting. Welding  and  Punching.  Conditions  of  Work  :  Principles  of  Forma- 
tion. Bending  and  Ring  Making.  Miscellaneous  t.xamples  of  Forged  Work. 
Cranks,  Model  Work,  and  Die  Forging.  Home-made  Forges.  The  Manipula- 
tion of  Steel  at  the  Forge.  (Continued  on  next  page.) 

DAVID   McKAY,  Publisher,  610  South  Washington   Square,   Philadelphia. 


HANDICRAFT  SERIES   (continued"). 

Glass  Working  by  Heat   and   Abrasion.     With  303  Engravings 
and  Diagrams. 

Contents.— Appliances  used  in  Glass  Blowing.  Manipulating  Glass  Tubing. 
Blowing  Bulbs  and  Flasks.  Jointing  Tubes  to  Bulbs  forming  Thistle  Funnels, 
etc.  Blowing  and  Etching  Glass  Fancy  Articles  ;  Embossing  and  Gilding  Flat 
Surfaces.  Utilising  Broken  Glass  Apparatus  ;  Boring  Holes  in,  and  Riveting 
Glass.  Hand-working  of  Telescope  Specula.  Turning,  Chipping,  and  Grinding 
G  ass.  The  Manufacture  of  Glass. 
Building  Model  Boats.  With  168  Engravings  and  Diagrams. 

Contents.- Building  Model  Yachts.  Rigging  and  Sailing  Model  Yachts. 
Making  and  Fitting  Simple  Model  Boats.  Building  a  Model  Atlantic  Liner. 
Vertical  Engine  for  a  Model  Launch.  Model  Launch  Engine  with  Reversing 
Gear.  Making  a  Show  Case  for  a  Model  Boat. 

Electric   Bells,   How  to  Make  and   Fit  Them.    With  162  En. 
graving  s  and  Diagrams. 

Contents. — The  Electr  c  Current  and  the  Laws  that  Govern  it.  Current 
Conductors  used  in  Electric-Bell  Work.  Wiring  for  Electric  Bells.  Elaborated 
Systems  of  Wiring;  Burglar  Alarms.  Batteries  for  Electric  Bells.  The  Con- 
struction of  Electric  Bells,  Pushes,  and  Switches.  Indicators  for  Electric-Bell 
Systems. 
Bamboo  Work.  With  177  Engravings  and  Diagrams. 

Contents.— Bamboo  :  Its  Sources  and  Uses.  How  to  Work  Bamboo.  Bamboo 
Tables.  Bamboo  Chairs  and  Seats.  Bamboo  Bedroom  Furniture.  Bamboo 
Hall  Racks  and  Stands.  Bamboo  Music  Racks.  Bamboo  Cabinets  and  Book- 
cases. Bambco  Window  Blinds.  Miscellaneous  Articles  of  Bamboo.  Bamboo 
Mail  Cart. 


ing  Horns.     Skinning,  Stuffing,   and  Casting   fish.     P,  eserving,  Cleaning,  and 

Dyeing  Skins.      Preserving   Insects,   and   Birds'  Eggs.      Cases  for   Mounting 

Specimens. 

Tailoring:.     With  180  Engravings  and  Diagrams. 

Co: tents.—  Tailors'  Requisites  and   Methods  of  Stitching.     Simple  Repairs 
and    .Pressing.      Relining,   Repocketing,  and  Recollaring.      How  to  Cut  and 
Make  Trousers.     How  to  Cut  and  Make  Vests.      Cutting  and  Making  Lounge 
and  Reefer  Jackets.     Cutting  and  Making  Morning  and  Frock  Coats. 
Photographic  Cameras  and  Accessories.    Comprising  How  TO 
MAKE  CAMERAS,   DARK  SLIDES,   SHUTTERS,   and  STANDS.     With  160 
Illustrations. 

Contents. — Photographic  Lenses  and  How  to  Test  them.    Modern  Half-plate 
Cameras.      Hand   and   Pocket    Cameras.      Ferrotype   Cameras.      Stereoscopic 
Cameras.     Enlarging  Cameras.     Dark  Slides.     Cinematograph  Management. 
Optical  Lanterns.    Comprising  THE  CONSTRUCTION  AND  MANAGEMENT 
OF  OPTICAL  LANTERNS    AND    THE    MAKING  OF  SLIDES.      With    160 
Illustrations. 

Contents. — Single  Lanterns.  Dissolving  View  Lanterns.  Illuminant  for 
Optical  Lanterns.  Optical  Lantern  Accessories.  Conducting  a  Limelight 
Lantern  Exhibition.  Experiments  with  Optical  Lanterns.  Painting  Lantern 
Slides.  Photographic  Lantern  Slides.  Mechanical  Lantern  S;ides.  Cinemato- 
graph Management. 
Engraving  Metals.  With  Numerous  Illustrations. 

Contents.  —  Introduction  and  Terms  used.  Engravers'  Tools  and  their  Uses. 
Elementary  Exercises  in  Engraving.  Engraving  Plate  and  Precious  Metals. 
Engraving  Monograms.  Transfer  Processes  of  Engraving  Metals.  Engraving 
Name  Plates.  Engraving  Coffin  Plates.  Engraving  Steel  Plates.  Chasing 
and  Embossing  Metals.  Etching  Metals. 
Basket  Work.  With  189  Illustrations. 

Contents. — Tools  and  Materials,  simple  Baskets.  Grocer's  Square  Baskets. 
Round  Baskets.  Oval  Baskets.  Flat  Fruit  Baskets.  Wicker  Elbow  Chairs. 
Basket  Bottle-casings.  Doctors'  and  Chemists'  Baskets.  Fancy  Basket  Work. 
Sussex  Trug  Basket.  Miscellaneous  Basket  Work.  Index 

DAVID  McKAY,  Publisher,  610  South  Washington  Square,    Philadelphia. 


HANDICRAFT  SERIES   (continued). 

Bookbinding.     With  125, Engravings  and  Diagrams. 

Contents.— Bookbinders'  Appliances.  Folding  Printed  Book  Sheets.  Beat- 
ing and  Sewing.  Rounding,  Backing,  and  Cover  Cutting.  Cutting  Book  Edges. 
Covering  Books.  Cloth-bound  Books,  Pamphlets,  etc.  Account  Books, 
Ledgers,  etc.  Coloring,  Sprinkling,  and  Marbling  Book  Edges.  Marbling 
Book  Papers.  Gilding  Book  Edges.  Sprinkling  and  Tree  Marbling  Book 
Covers.  Lettering,  Gilding,  and  Finishing  Book  Covers.  Index. 
Bent  Irpn  Work.  Including  ELEMENTARY  ART  METAL  WORK.  With 
269  tngravings  and  Diagrams. 

Contents.— Tools  and  Materials.  Bending  and  Working  Strip  Iron.  Simple 
Exercises  in  Bent  Iron.  Floral  Ornaments  for  Bent  Iron  Work.  Candlesticks. 
Hall  Lanterns.  Screens,  Grilles,  etc.  Table  Lamps.  Suspended  Lamps  and 
Flower  Bowls.  Photograph  Frames.  Newspaper  Rack.  Floor  Lamps. 
Miscellaneous  Examples.  Index. 

Photography.     Witn  7°  Engravings  and  Diagrams. 

Contents.—  i'ue  Camera  and  its  Accessories.  The  Studio  and  Darkroom. 
Plates.  Exposure.  Developing  and  Fixing  Negatives.  Intensification  and 
Reduction  of  Negatives.  Portraiture  and  Picture  Composition.  Flashlight 
Photography.  Retouching  Negatives  Processes  of  Printing  from  Negatives. 
Mounting  and  Finishing  Prints.  Copying  and  Enlarging.  Stereoscopic 
Photography.  Ferrotype  Photography.  Index. 
Upholstery.  With  162  Engravings  and  Diagrams. 

Contents.— Upholsterers'  Materials.  Upholsterers'  Tools  and  Appliances. 
Webbing,  Springing,  Stuffing,  and  Tufting.  Making  Seat  Cushions  and  Squabs. 
Upholstering  an  Easy  Chair.  Upholstering  Couches  and  Sofas.  Upholstering 
Footstools,  Fenderettes,  etc.  Miscellaneous  Upholstery.  Mattress  Making 
and  Repairing.  Fancy  Upholstery.  Renovating  and  Repairing  Upholstered 
Furniture.  Planning  and  Laying  Carpets  and  Linoleum.  Index. 
Leather  Working.  With  152  Engravings  and  Diagrams. 

Contents.— Qualities  and  Varieties  of  Leather.  Strap  Cutting  and  Making. 
Letter  Cases  and  Writing  Pads.  Hair  Brush  and  Collar  Cases.  Hat  Cases. 
Banjo  and  Mandoline  Cases.  Bags.  Portmanteaux  and  Travelling  Trunks. 
Knapsacks  and  Satchels.  Leather  Ornamentation.  Footballs.  Dyeing 
L-ather.  Miscellaneous  Examples  of  Leather  Work.  Index. 
Harness  Making.  With  197  Engravings  and  Diagrams. 

Contents.— Harness  Makers'  Tools.     Harness  Makers'  Materials.     Simple 
Exercises  in  Stitching.    Looping.    Cart  Harness.    Cart  Collars.    Cart  Saddles. 
Fore  Gear  and  Leader  Harness.     Plough  Harness.     Bits,  Spurs,  Stirrups,  and 
Harness  Furniture.     Van  and  Cab  Harness.     Index. 
Saddlery.     With  99  Engravings  and  Diagrams. 

Contents.— Gentleman's  Riding  Saddle.  Panel  for  Gentleman's  Saddle. 
Ladies'  Side  Saddles.  Children's  Saddles  or  Pilches.  Saddle  Cruppers,  Breast- 
plates, and  other  Accessories.  Riding  Bridles.  Breaking-down  Tackle  Head 
Collars.  Horse  Clothing.  Knee-caps  and  Miscellaneous  Articles.  Repairing 
Harness  and  Saddlery.  Re-lining  Collars  and  Saddles.  Riding  and  Driving 
Whips.  Superior  Set  of  Gig  Harness.  Index. 

Knotting  and  Splicing,  Ropes  and  Cordage.    With  208 

Engravings  and  Diagrams. 

Contents.— Introduction.  Hope  Formation.  Simple  and  Useful  Knots. 
Eye  Knots,  Hitches  and  Bends.  Ring  Knots  and  Kope  Shortenings,  'lies 
and  Lashings.  Fancy  Knots.  Rope  splicing.  Working  Coroage.  Ham- 
mock Making.  Lashings  a.id  Ties  for  bcaffolding.  Splicing  and  Socketing 
Wire  Ropes.  Index. 

Beehives  and  Beekeepers'  Appliances.    With  155  Engravings 

and  Diagrams. 

Contents.— Introduction.  A  Bar-Frame  Beehive.  Temporary  Beehive. 
Tiering  Bar-Frame  Beehive.  The  "  W.  B.  C."  Beehive.  Furnishing  and 
Stocking  a  Beehive.  Observatory  Beehive  for  Permanent  Use.  Observatory 
Beehive  for  Temporary  Use.  Inspection  Case  for  Beehives.  Hive  for  Rear- 
ing Queen  Bees.  Super-Clearers.  Bee  Smoker.  Honey  Extractors.  Wax 
Extractors.  Beekeepers'  Miscellaneous  Appliances.  Index. 

DAVID  McKAY,  Publisher,  610   South   Washington  Square,  Philadelphia. 


MOTOR  BICYCLE 
BUILDING 


WITH  NUMEROUS   ENGRAVINGS  AND    DIAGRAMS 


EDITED  BY 

PAUL     N.     HASLUOK 


\FTS,      ETC.    ETC. 


PHILADELPHIA 

DAVID     McKAY,     PUBLISHER 

(510,  SOUTH  WASHINGTON  SQUARE 

1906 


Engine*™* 
Ubrary 
TL 


PREFACE. 


THIS  Handbook  contains,  in  form  convenient  for 
everyday  use,  a  number  of  articles  contributed  by 
a  cycle  and  motor  maker  and  expert— Mr.  W.  Travers 
—to  WORK,  one  of  the  weekly  journals  it  is  my 
fortune  to  edit.  The  chapter  on  ignition  coils  is 
from  the  pen  of  Mr.  G.  E.  Bonney,  the  well-known 
writer  on  practical  electrical  subjects. 

Readers    who    may    desire    additional    information 

respecting  special   details  of    the   matters  dealt  with 
x. 

in  this  Handbook,  or  instructions  on  kindred  subjects, 

should   address  a  question   to  WOKK,  so  that  it  may 
be  answered  in   the  columns  of  that  journal, 
a 

P.  N.  HASLUCK. 

La  Belle  Sauvage,  London. 
October,  1906. 


733510 


CONTENTS. 

CHAPTER  PAGE 

I.— Frame  for  Motor  Bicycle    ....        9 

II. — Patterns  for  Frame  Castings      ...       10 

III. — Building  Frame  from  Castings  ...      32 

IV.— Making  34-H.P.  Petrol  Motor    ...       47 

V. —Spray  Carburettor  for  3^-H.P.  Motor        .       97 

VI.— Ignition  Coils  for  Motor  Cycles        .  *      .104 

VII.— Light-weight  Petrol  Motor  for  Attachment 

to  Roadster  Bicycle         .        .        •        .118 

VIII.— Spray  Carburettor  for  Light-weight  Motor    149 

Index    .  15~ 


LIST    OF    ILLUSTRATIONS. 


FIG.  PAGE 

1. — Working      Drawing      of 

Motor  Bicycle  Frame  .  13 

2.— Bottom  Bracket       .       .  17 

3,  4.— Back  Fork  Crown        .  18 
5.— End      of      Back      Fork 

Crown  .  .  .  .19 
6,  7.— Rear  Engine  Lug  .  20 
8,  9.— Front  Engine  Lug  .  21 
10, 11.— Left-hand  Fork  End  .  22 
12.— Top  Member  of  Left- 
hand  Fork  End  .  .  22 
13.— Back  Stay  Eye  .  .  22 
14.— Front  Fork  End  .  .  22 
15, 16.— Patterns  for  Top  and 

Bottom  Head  Lugs       .  23 

17.— Seat  Lug     ....  24 

18.— Rear  Part  of  Seat  Lug  .  24 

19. — Lower  Horizontal  Lug   .  25 

20,  21.— Girder  Tube  Lugs     .  26 

22,  23.— Front  Fork  Crown     .  27 

24,  25.— Steering  Tube  Lug    .  28 

26, 27.— Engine  Plate       .       .  2£ 

28,  29.— Ball-race       ...  37 
30.— Bottom  Bracket  Axle  in 

Position    ....  38 

31,  32.— Bracket  Lock-nut       .  3S 

33.— Engine  Plate  Belt  .       .  41 
34.— Vertical       Section       of 

3J-h.p.  Petrol  Engine   .  48 
35,  36.— Vertical  Section  and 

Plan  of  Engine  Cylinder  49 
37.— Plan  of  Bottom  or  Open 

End  of  Cylinder     .       .  51 
38.— Section  of  Finished  Pis- 
ton        55 

39. — Section    of    Piston     on 

Line  X  X  (Fig.  38)         .  57 


FIG.  PAGE 

40, 41.— Two       Methods       of 

Jointing  Piston  Rings.  58 
42.— Piston     Ring,     showing 

Eccentricity  of  Bore    .  58 
43.— Exhaust  Valve  Guide    .  59 
44,  45.— Exhaust  Valve   .        .  60 
46,  47.— Inlet  Valve  Body       .  61 
48-50.— Head        and        Stem, 
Washer    and    Lock-nut 
of  Inlet  Valve        .       .  63 
51.— Spring    Washer    of    Ex- 
haust Valve     ...  63 
52.— Plan    of    Cylinder    End 

of  Crank  Case  .  .  64 
53, 54.— Side  Elevation  and 
Vertical  Section  of 
Crank  Case  .  .  .67 
55.— Section  of  Gear  Cover  .  71 
56,  57.— Tappet-rod  Bush  .  73 
58,  59.— Valve-lift  Lever  .  .  73 
60,  61.— Connecting  Rod  .  .  75 
62,  63.— Union  Nut  .  .  76 
64,  65.— Flywheel  ...  77 
66.— Main  Shaft,  Pulley  Side  78 
67.— Main  Shaft,  Gear  Side  .  79 
68.— Crank  Pin  .  .  .  .79 
69.— Half-time  Shaft  .  .  81 
70.— Tappet  Rod  .  81 
71.— Circular  Plate  of  Tap- 
pet Rod  .  .  .  .82 
72.— Gudgeon  Pin  ...  82 
73,  74.— Tool  for  Cutting  Key- 
ways  in  Lathe  .  .  83 
75.— Section  of  Engine  Pulley  85 
76.— Locking  Plate  ...  86 
77, 78.— Exhaust  Cam  .  .  87 
79,  80.— Large  Gear  Wheel  .  88 


LIST   OF   ILLUSTRATIONS. 


FIG.  PAGE 

81,  82.— Small  Gear  Wheel    .    89 
83.— Inlet    Tube    from    Car- 
burettor   .       .       .       .91 
84,      85.— Bottom     Plate     of 

Silencer  ....  94 
86,  87.— Top  Plate  of  Silencer  95 
88.— Tube  for  Silencer  .  .  96 
89.— Pin  or  Bolt  for  Silencer  96 
90.— Sectional  View  of  Car- 
burettor ....  99 
91.— Cover  Piece  .  .  .100 
92.— Base  Piece  .  .  .100 
93. — Pattern  for  Gauze  Cone- 
piece  .  .  .  .101 
94.— Bridge  Piece  .  .  .102 
95.— Diagram  of  Condenser 

Layers  .  .  .  .111 
96.— Longitudinal  Sectional 

Elevation  of  Trembler  .  112 
97. — Transverse  Sectional 

Elevation  of  Trembler  113 
98.— Plan  of  Armature  and 

Spring  .  .  .  .113 
99.— Plan  of  Trembler  on 

End  of  Coil      .       .        .114 
100.— Diagram    of    Coil    Con- 
nections .       .       .       .115 
101. — Diagram  showing 

Working    of    Ignition 
Coils         .       .       .       .117 
102.— Section  of  Light-weight 

Motor  Crank  Case  .  118 
103.— Plan  of  Light-weight 

Motor  Crank  Case  .  119 
104, 105.— Crank  Case  Cover  .  121 
106, 107.— Cover  for  Exhaust 

Cam  Chamber  .  .  123 
108.— Section  of  Light-weight 

Motor  Cylinder    .        .  125 


FIG.  PAGE 

109.— Half-plan       of      Light- 
weight   Motor    Cylin- 
der Head        .       .       .127 
110.— Exhaust  Valve  Guide  .  128 
111.— Exhaust  Push-rod 

Guide  .  .  .  .130 
112, 113.— Exhaust  Valve  .  131 
114.— Inlet  Valve  .  .  .132 
115, 116.— Body  of  Inlet  Valve  133 
117, 118.— Piston  of  Light- 
weight Motor  .  .  135 
119.— Gudgeon  Pin  for  Piston  136 
120.— Piston  Ririg  Joint  .  137 
121. — Better  Form  of  Piston 

Ring  Joint      .        .        .137 
122.— Piston  Ring  Bored  Ec- 
centrically    .        .       .138 
123, 124.— Section    and  Eleva- 
tion of  Connecting  Rod  140 
125.— Shaft     and     Crank     of 

Light-weight  Motor  .  141 
126.— Crank  Casting  .  .  .143 
127.— Section  of  Flywheel 

and  Pulley     .       .       .145 
128.— Exhaust  Cam  Shaft      .  146 
129.— Exhaust  Cam  .       .       .147 
130.— Ignition  Cam  .        .       .147 
131, 132.— Section  and  Eleva- 
tion    of     Spray     Car- 
burettor    for     Light- 
weight Motor        .       .  151 
133.— Valve    Stem    Guide    of 

Spray  Carburettor  .  152 
134. — Section  of  Carburettor 

Throttle  Stem  .  .  154 
135.— Pattern  of  Gauze  Cone  .  155 
136. — Induction  Pipe  and 

Union  Nut  .  .  .156 
137— Plan  of  Union  Nut  .  157 


MOTOR  BICYCLE  BUILDING. 


CHAPTER    I. 

FRAME   FOR   MOTOR   BICYCLE. 

IN  this  handbook  it  is  intended  fully  to  describe 
the  work  of  building  a  motor  cycle,  right  from  the 
pattern  making,  and  not  merely  to  show  how  to 
build  it  up  from  a  set  of  purchased  fittings.  Of 
course,  where  time  is  a  consideration,  and  where 
only  one  frame  is  required,  it  would  no  doubt 
be  cheaper  to  buy  a  set  of  standard  frame  fittings 
and  put  these  together ;  but  thousands  of  workers 
possess  sufficient  skill  to  make  their  own  patterns, 
and  to  work  up  the  castings,  from  the  instructions 
given  in  this  handbook — instructions  that  will  be 
specially  useful  to  homeworkers  who  have  more 
time  than  cash  to  spare,  and  to  small  makers  and 
repairers  who  may  have  to  construct  several 
frames  during  the  season.  Any  reader  will  be  able 
to  build  the  frame  from  a  set  of  finished  fittings, 
as  the  design  is  a  standard  one.  The  illustrations 
show  finished  sizes  of  castings,  etc.,  when  machined, 
and  not  the  pattern  sizes. 

To  those  who  have  built  ordinary  cycle  frames 
(work  which  is  fully  described  in  a  companion 
handbook,  "  Cycle  Building  and  Repairing  ")  no 
difficulty  should  be  found  in  building  a  frame 
for  a  motor  cycle.  Much  of  the  work  is  the  same, 
and  the  various  fittings  differ  very  little  from 
those  of  an  ordinary  cycle.  The  tubes  and  most 


1»  MOTOR    BICYCLE    BUILDING. 

of  the  lugs  are  certainly  heavier  and  stouter ; 
therefore  proper  brazing  facilities  must  be  at 
hand.  A  lamp  or  blowpipe  which  is  only  just 
powerful  enough  to  braze  a  light  cycle  lug  will 
probably  fail  to  braze  the  rear  engine  lug,  which 
is  somewhat  heavy  and  large,  or  the  rear  portion 
of  the  bottom  bracket,  where  it  is  joined  to  the 
back  fork  bridge  by  the  If-in.  tube. 

Dimensions. — The  two  wheels  are  28  in.  by  2  in. 
2j  in.  w7ould  be  preferable  if  a  powerful  engine  is 
fitted,  the  larger  diameter  of  tyres  tending  to 
lessen  vibration,  thus  adding  much  to  the  comfort 
of  riding. 

The  frame  measures  2  ft.  from  the  top  of  the 
seat  lug  to  the  centre  of  the  bracket.  This  height 
of  frame  is  suitable  for  riders  not  less  than 
5  ft.  7  in.  in  height ;  a  rider  not  more  than 
5  ft.  6  in.  would  be  better  suited  with  a  23-in. 
frame.  This  will  mean  a  corresponding  shorten- 
ing of  the  head  tube  (to  retain  the  horizontal 
position  of  the  top  tube)  and  the  front  girder 
tube. 

The  main-frame  tubes  are  of  lg-in.  diameter, 
with  head  tube  1^  in. 

The  back  forks  and  back  stays  are  of  D-section, 
cranked  out  on  the  left-hand  side  of  the  machine, 
looking  from  the  back,  to  give  clearance  to  the 
belt  and  belt  rim;  or  patterns  can  be  made  for 
the  cranked  portion,  and  malleable  castings  used 
for  these  parts.  It  will  probably  be  found  prefer- 
able to  use  cranked  tubes,  which  can  be  purchased 
ready  bent,  rather  than  go  to  the  trouble  of  mak- 
ing patterns  for  them;  these  will  be  lighter  and 
easier  to  fit  up,  besides  lessening  the  amount  of 
pattern-making  necessary. 

The  front  forks  are  oval  in  section,  with  gir- 
der tube*  |  in.  round,  swaged  down  to  A  in.  at 
each  end.  The  front  fork  tube  is  of  lg-in.  dia- 
meter, and  should  be  stoutly  butted  at  the  crown 
end  to  at  least  No.  13  or  No.  14  gauge. 


FRAME    FOR    MOTOR    BICYCLE.  11- 

The  handle-bar  should  be  of  good  width, 
upturned,  and  brought  well  back  towards  the 
saddle. 

This  frame  is  suitable  for  an  engine  up  to 
3j  h.p.,  this  being  the  largest  it  is  advisable  to 
go  to  with  air  cooling.  With  a  3i-h.p.  engine, 
the  frame  would  be  suitable  for  use  with  a  trailer, 
side  car,  or  fore  car. 

Wheels. — The  wheels  should  be  built  up  with 
No.  12  or  No.  13  gauge  spokes;  if  for  use  with  a 
fore  car,  the  rear  wheel  should  be  built  of  No.  12 
gauge  at  least.  The  hubs  had  better  be  purchased ; 
an  Eadie  coaster  motor  hub  for  the  back,  and  an 
ordinary  motor  front  hub,  with  f-in.  spindle,  will 
be  suitable.  The  Eadie  hub,  with  a  front  wheel 
rim  brake,  will  give  all  the  braking  power  re- 
quired. 

Drive. — The  drive  is  by  |-in.  V-belt,  if  for  use 
as  a  single;  or  §-in.,  or  even  1-in.,  for  use  with  a 
fore  car.  The  design  and  position  of  the  engine 
allows  of  a  good  long  belt  being  used.  Cranks 
should  be  7-in.  throw,  and  gear  low,  about  54  in. 
or  56  in.  A  suitable  engine  gear  will  be  a  ratio 
of  about  5j  to  1  for  all-round  work  with  a  trailer 
or  fore  car,  or  as  single  about  5  to  1 — say  4-in. 
engine  pulley  with  a  20-in.  rim  pulley.  The  size 
of  the  pulley  on  the  rim  must  be  decided  upon 
before  building  the  frame,  to  get  the  proper  posi- 
tion of  the  cranked  portion  of  the  back  fork  and 
stay.  The  position  as  shown  in  Fig.  1  (p.  13)  is 
intended  for  a  20-in.  rim  pulley. 

Mud-guards. — Ample  mud-guards,  3j  in.  wide, 
should  be  fitted  to  both  wheels,  the  rear  guard 
coming  through  the  fork  crown  and  continuing 
3  in.  or  4  in.  below.  The  front  guard  will  bo 
best  fitted  in  two  parts,  the  front  portion  extend- 
ing some  9  in.  or  10  in.  in  front  of  the  crown, 
and  supported  by  another  pair  of  stays  to  the 
front  wheel  axle,  besides  being  screwed  to  the 
front  of  the  crown.  These  mud-guards  stays  must 


12  MOTOR    BICYCLE    BUILDING. 

be  considerably  stouter  than  ordinary  cycle  stays, 
and  should  be  made  of  |-in.  by  g-in.  mild  steel 
strip,  firmly  riveted  to  guards  with  copper  rivets 
and  washers.  Should  it  be  desired  to  use  2i-in. 
tyres,  the  fork  crowns,  both  back  and  front, 
should  be  made  J  in.  wider  than  here  designed ; 
and  in  that  case  4-in.  mud-guards  would  be  prefer- 
able to  3^-in. 

Working  Drawings. — The  first  thing  to  do  will 
be  to  make  a  full-size  working  drawing,  as  Fig.  1, 
in  chalk,  on  the  wall  or  floor  of  the  workshop, 
where  it  will  not  be  readily  rubbed  out.  Start 
by  marking  an  horizontal  ground  line.  From  a 
centre  1  ft.  2  in.  above  this,  describe  the  circle 
for  the  rear  wheel;  1  ft.  7i  in.  from  this  centre 
and  11  in.  from  the  ground  line  will  be  the  bottom 
bracket  centre.  Mark  off  the  bracket,  and  draw 
in  the  back  forks  and  fork  end,  at  an  angle  of 
64  degrees.  From  the  back  fork  draw  in  the 
diagonal  or  down  tube,  which  should  be  2  ft.  (or 
less  if  necessary)  from  the  centre  of  the  bracket. 
The  back  stay  can  then  be  marked  in.  Draw  the 
top  horizontal  tube  2  ft.  7^  in.  from  the  centre  line 
of  the  down  tube  to  the  centre  line  of  the  head 
tube.  Fill  in  the  head  tube  and  lugs,  after  draw- 
ing the  steering  line  at  the  same  angle  as  the 
down  tube;  2|  in.  in  advance  of  this  steering  line 
and  1  ft.  2  in.  from  the  ground  line  will  be  the 
front  wheel  hub  centre.  The  bottom  front  tube 
can  now  be  drawn  in  at  an  angle  of  56  degrees 
from  the  steering  centre.  The  exact  length 
of  this  tube  will  be  determined  by  the  size 
of  the  crank  case  of  the  engine  used,  but  with  an 
engine  as  shown  the  length  from  the  centre  line  of 
the  head  to  the  centre  of  the  f-in.  bolt  securing 
the  engine  to  the  lug  will  be  1  ft.  7  in.  The  tube 
and  lug  from  the  bottom  bracket  to  the  rear  engine 
lug  are  then  drawn  in,  the  distance  from  the 
centre  of  the  bracket  to  the  centre  of  the  bolt 
being  1\  in.  The  lower  horizontal  tube  will  be 


FRAME    FOR    MOTOR    BICYCLE. 


14  MOTOR    BICYCLE    BUILDING. 

7J  in.  from  the  top— that  is,  7J  in.  space  between 
the  two  tubes.  The  stays  which  support  the  centre 
of  the  girder  tubes  are  2  in.  from  the  centre  line 
of  the  steering  tube  to  the  centre  of  the  f-in.  tubes. 
The  mud-guards  are  arranged  so  as  to  give  lj-m- 
clearance  from  the  tyres.  With  this  drawing 
carefully  made,  it  will  be  easy  to  test  the  various 
angles  of  the  patterns,  and,  when  building,  to 
see  that  the  various  tubes  and  lugs  are  accurately 
fitted  together  before  brazing  up. 

Tubes. — The  following  are  the  sizes  of  the  tubes 
and  the  gauge  numbers  :  Top  tube,  2  ft.  6|  in.  by 
l\  in.,  No.  20;  lower  horizontal  tube,  2  ft.  2|  in. 
by  Ij  in.,  No.  20;  head  tube,  6|  in.  by  1^  in., 
No.  20;  down  tube,  1  ft.  11|  in.  by  l£  in.,  No.  20; 
front  tube,  1  ft.  65  in.  by  lg  in.,  No.  14;  back  stays, 
D-section,  1  ft.  8i  in.,  No.  18;  back  forks,  D-sec- 
tion,  1  ft.  If  in.,  No.  18;  back  fork  crown  to 
bracket,  3  in.  by  If  in.,  No..  20;  bracket  to  rear 
engine  lug,  6^  by  If  in.,  No.  20;  front  forks  oval, 
No.  17  gauge  for  28-in.  wheel,  to  give  1|  in.  clear- 
ance for  tyre;  girder  tubes  (two),  1  ft.  11  in.  by 
|  in.,  No.  18,  swaged  to  i  in.  at  each  end;  steering 
tube,  llj  in.  by  1|  in.,  No.  16,  butted  to  No.  13  or 
No.  14;  handle-bar,  1  ft.  10  in.  wide  by  1  in., 
No.  17,  which  will  take  3  ft.  3  in.  of  tubing;  han- 
dle-bar tube,  1  in.  by  9  in.,  No.  16;  seat  pillar, 
8  in.  by  1  in.,  No.  18;  top  of  seat  pillar,  5  in.  by 
I  in.,  No.  16.  These  lengths  will  allow  for  the 
ends  being  hollowed  out  to  fit  round  the  connect- 
ing parts,  a  method  which  greatly  strengthens 
the  joints. 

Wheel  Base,  etc. — The  wheel  base  of  the  machine 
is  4  ft.  7  in.  ;  distance  from  centre  of  bottom 
bracket  to  centre  of  engine,  1  ft.  Oj  in. ;  back  fork 
ends,  5j  in.  wide  (to  suit  Eadie  motor  coaster 
hub) ;  front  fork  ends,  4j  in.  apart. 

Tandem  Motor  Bicycle. — It  is  not  intended  here 
to  describe  the  construction  of  a  tandem,  but  the 
work  will  not  present  difficulty  to  a  worker  who 


FRAME    FOR    MOTOR    BICYCLE.  15 

succeeds  in  making  an  ordinary  motor  cycle  ac- 
cording to  the  instructions  given  in  this  book.  It 
may  be  mentioned,  however,  that  the  diameter- of 
the  tubes  for  a  tandem  motor  bicycle  with  lady's 
frame  at  back  will  be  regulated  by  the  make  and 
type  of  fittings  used,  but  the  gauges  should  be  as 
follows  :  Bottom  front  tube,  No.  14 ;  down  tubes, 
No.  18;  top  and  bottom  horizontal  tubes,  No.  20; 
head  tube,  No.  20;  bottom  bracket  connecting 
tubes,  if  |-in.  twin,  No.  16,  if  li-in.  single  tube, 
No.  18;  rear  forks,  No.  16;  rear  stays,  No.  20; 
front  forks,  No.  17,  with  No.  18  girder  stays; 
steering  tube,  No.  16,  butted  12  at  the  crown. 
Cnater  Lea  and  Co.  make  several  designs  of  tan- 
dem fittings  that  would  be  suitable  for  the  pur- 
pose. 


16 


CHAPTER    II. 

PATTERNS    FOR   FRAME    CASTINGS. 

Introduction. — The  method  of  turning  out  the  pat- 
terns will  now  be  considered.  As  making  the  core- 
boxes  for  some  of  the  patterns  will  probably  be 
the  most  difficult  part  of  the  work,  these  will  be 
dispensed  with  as  much  as  possible,  and  plain 
prints  and  cores  used  whenever  practicable.  If  a 
number  of  sets  have  to  be  made  from  the  patterns, 
it  would  be  advisable  to  make  proper  core-boxes 
for  those  particular  patterns  requiring  them. 

Wood  for  Patterns. — One  of  the  best  woods  to 
use  for  the  patterns  is  mahogany,  but  well-sea- 
soned white  pine  is  cheaper,  and  easier  to  work, 
and  this,  if  well  varnished,  will  stand  a  few  sets 
of  castings  being  made  from  them. 

Bottom  Bracket. — Fig.  2  is  a  side  view  of  the 
bottom  bracket;  for  this,  plain  prints  and  cores 
may  be  used.  Turn  up  the  body  part,  which  is 
3|  in.  long  by  If  in.  in  diameter,  finished  casting, 
making  due  allowance  for  shrinkage  and  machin- 
ing. As  only  the  two  end  faces  of  the  outside  of 
the  casting  will  be  machined,  Ta¥  in.  for  machining, 
and  another  -J-  in.  for  shrinkage,  should  be  al- 
lowed. It  is  usual  to  allow  about  /V  in-  ^°  *ne 
foot  for  shrinkage,  but  with  these  small  castings, 
where  the  length  does  not  exceed  2  in.  or  3  in., 
it  will  generally  be  found  that  what  is  lost  by 
shrinkage  is  made  up  by  the  moulder  "  rapping  " 
the  pattern  in  the  sand,  so  that  as  a  rule  it  will 
scarcely  be  worth  while  to  take  shrinkage  into 
consideration.  In  turning  up  the  body  part  of 
the  bracket  leave  a  core-print  at  each  end,  £  in. 


PATTERNS    FOR    FRAME    CASTINGS.  17 

long  by  1  -,s-g  in.  in  diameter,  rounding  off  the 
ends  slightly,  so  that  the  pattern  will  leave  the 
sand  easily. 

Now  turn  up  the  three  tube  members  to  take 
the  rear  and  front  If-in.  tubes  and  the  l|-in.  down 
tube.  These  members,  when  the  castings  are 
machined,  should  be  T^  in.  larger  in  diameter  at 
the  extreme  thin  edge  than  the  bore,  and  at  the 
root,  where  they  join  the  body  part,  quite  fV  in- 
larger  than  the  bore ;  this  gives  a  taper  to  the 
lug  of  about  3  degrees.  The  core-prints  for  those 
members  must  be  longer  by  about  J  in.  than  the 
depth  the  core  is  to  go  in  the  pattern,  so  that  it 


Fig.  2.— Bottom  Bracket. 

may  balance  in  the  mould,  being  supported  at  the 
one  end  only,  and  not  at  both  ends,  as  is  the 
body  core.  The  length  of  the  If-in.  members  will 
be  2  in.  from  the  centre  of  the  bracket,  and  the 
l|-in.  members  If-in.  from  the  centre.  The  core- 
prints  will  be  If  in.  and  If  in.  long  respectively, 
and  |  in.  smaller  in  diameter  than  the  size  of  the 
finished  bores  for  the  tubes.  These  three  members 
must  be  hollowed  out  at  the  ends,  and  fitted  to- 
gether on  to  the  body  part  at  the  angles  shown  in 
t'ig.  2,  and  then  tested  for  accuracy  on  the  full- 
size  drawing  before  being  finally  glued  and 
pegged  on.  All  three  members  are  fitted  centrally 


IS 


MOTOR    BICYCLE    BUILDING. 


to  the  body.  There  must  be  no  sharp  angles  where 
the  various  parts  join;  the  joints  should  be 
rounded  and  smoothed  off  neatly.  To  one  not 
used  to  this  class  of  work,  some  difficulty  will 
be  found  in  doing  it  neatly,  in  which  case  sharp 
corners  may  be  filled  up  with  good  hard  wax, 
applied  hot  and  smoothed  off  when  cold.  Care 
must  be  taken  that  all  three  members  are  at  right 


Fig.  4. 
Figs.  3  aad  4.— Back  Fork  Crown. 

angles  to  the  body  part.  No  provision  has  been 
made  on  this  pattern  for  securing  the  bracket 
cups  in  position,  as  it  is  intended  that  these 
should  be  made  extra  wide,  and  fitted  with  lock- 
nuts  to  lock  against  the  faces  of  the  bracket. 
Alternative  methods  would  be  to  provide  a  lug 
at  each  en$  for  a  locking  cotter  pin  and  nut,  as 
in  the  B.S.A.  and  other  brackets;  or  to  fit  a 


PATTERNS    FOE,    FRAME    CASTINGS.  19 

small  set-pin  and  nut  to  press  on  to  the  bracket 
discs — in  this  case  the  thickness  of  the  bracket 
shell  would  have  to  be  increased  by  fitting  a  small 
circular  piece,  about  -^  in.  thick,  on  to  each  end 
of  the  pattern,  so  that  a  good  thread  may  be 
tapped  in  for  the  set  pin.  In  adopting  either  of 
these  alternative  methods,  the  ordinary  standard 
bracket  discs  may  be  used. 

Back  Fork  Crown. — The  back  fork  crown 
(Figs.  3  and  4)  is  a  pattern  for  which  it  will 
be  necessary  to  make  a  core-box,  as  the  coring 
necessary  is  not  straight  and  circular,  like  the 
bracket,  but  irregular  in  formation.  The  pat- 
tern should  be  made  in  four  pieces — the  turned 
part  for  the  If -in.  tube,  the  body,  and  the  two 
end  pieces  for  the  back  forks.  The  turned  part 
will  be  the  same  as  the  two  large  ends  of  the 


Fig.  5. — End  of  Back  Fork  Crown. 

bottom  bracket,  except  that  the  print  will  need 
to  be  only  J  in.  or  f  in.  long,  as  the  core  will  be 
supported  in  the  mould  at  two  other  points, 
namely,  the  two  D-section  parts  of  the  back  fork 
lugs.  The  body  part  will  be  made  with  the  grain 
running  across  the  pattern.  After  the  top  part 
has  been  roughly  turned  and  the  body  cut  roughly 
to  shape,  the  top  may  be  let  into  the  body  and 
glued  up ;  then  again  returned  to  the  lathe,  and 
the  junction  of  the  two  and  the  top  of  the  shoul- 
ders turned  to  shape  as  far  as  possible.  The  two 
D-section  ends  are  afterwards  cut  to  shape  as  in 
Fig.  5,  and  dowelled  and  glued  on.  The  width 
of  the  crown  over  all  is  4|  in.,  and  the  inside 
width  between  the  fork  lugs  2f  in.  The  finished 
size  of  these  fork  lugs  (D-section)  is  1T^  in.  by 
-J-iin.,  and  the  core-prints  should  be  the  same  sec- 


•20 


MOTOR    BICYCLE    BUILDING. 


tion,  Jl  in.  by  T7^  in.,  and  |  in.  long.  The  core-box 
is  made  in  halves  dowelled  together,  and  must 
be  carved  out  so  that  a  uniform  thickness  of 
metal,  about  J  in.,  is  left  all  over  the  casting. 
It  will  require  accurate  work.  The  prints  on  the 
pattern  must  fit  the  core-box  accurately  when 
closed  up.  The  two  D-section  prints  must  fit  into 
the  D  ends  of  the  core-box,  and  the  lT9far-in.  print 
must  fit  the  other  end  of  the  core-box.  The  over- 
all length  of  the  box  is  the  same  as  the  over-all 
length  of  the  pattern  (over  the  end  of  the  prints), 
so  that  the  core  made  in  the  box  will  drop  snugly 
into  the  impression  left  in  the  sand  by  the  pat- 


Fig.  6.  Fig.  7. 

Figs.  6  and  7. — Rear  Engine  Lug. 

tern.  In  turning  the  top  part  of  the  pattern, 
leave  the  end  rounded,  so  that  it  may  come  away 
from  the  sand  easily,  and  also  chamfer  off  the 
two  ends  of  the  D  prints  for  the  same  reason. 

Engine  Lugs. — The  rear  engine  lug  is  shown 
in  front  elevation  at  Fig.  6  and  in  end  view  at 
Fig.  7,  similar  views  of  the  front  engine  lug  being 
given  at  Figs.  8  and  9.  The  rear  lug  is  made  in  two 
pieces,  and  no  core-box  is  required.  The  body 
part  is  turned  to  the  dimensions  given  in  the 
illustrations,  due  allowance  being  made  for  facing 
up  the  ends.  The  core-print  on  each  end  will 
be  f  in.  in  diameter  by  |  in.  long.  The  right- 


PATTERNS    FOR    FRAME    CASTINGS.  21 

angle  member  to  take  the  If-in.  tube  will  be  the 
same  as  the  large  members  on  the  bracket  pattern, 
the  same  instructions  also  applying  as  regards 
the  filling  up  sharp  corners  and  the  length  of  the 
core-print  to  balance  the  core  in  the  mould.  The 
front  engine  lug  is  the  same  as  the  rear  engine 
lug,  only  the  right-angle  member  is  to  receive 
l|-in.  tubing  instead  of  l|-in.,  and  must  be  made 
smaller  to  correspond. 

Eear  Fork  Ends. — Fig.  10  shows  one  of  the 
rear  fork  ends  (left-hand  side),  Fig.  11  being  an 
end  view  to  show  the  section.  This  pattern  may 


..J-...JI 


Fig.   8.  Fipr.   9. 

Figs.  8  and  9. — Front  Engine  Lug. 

be  made  in  two  pieces,  the  main  part  being  a 
piece  of  3^  in.  by'  1-^  in.  by  ^  in.,  the  grain 
running  with  the  length.  The  slot  for  the  spin- 
dle should  be  made  1|-  in.  by  /^  in.  full,  or  ^  in. 
bare,  to  allow  filing  out  to  i  in.  in  the  casting. 
The  D-section  end  for  the  b-ck  fork  is  1T^  in.  by 
-},V  in.,  the  same  as  the  ends  of  the  back  fork 
crown  (see  Fig.  5).  The  top  portion,  for  the  top 
backstay,  is  made  from  a  separate  piece,  and  is 
dovetailed  and  glued  on,  the  D  being  T|-  in.  by 
y9^  in.  finished  size  (see  Fig.  12).  The  centre  of 
both  D  portions  is  cut  out  for  lightness.  The  fork 
end  is  ^V  in.  thick,  the  raised  portion  being 


22 


MOTOR    BICYCLE    BUILDING. 


formed  by  cutting  out  to  shape  two  thin  slips 
of  wood  and  gluing  in  place,  making  the  com- 
bined thickness  at  this  part  J  in.  The  ends  may 
be  left  square  or  rounded,  as  shown  in  the  end 
view,  Fig.  11,  to  receive  the  chain  adjusters.  It 
will  be  necessary  to  make  another  pattern  to  pair 
with  this,  for  the  right-hand  side,  unless  the  top 
portion  is  made  detachable,  so  that  it  can  be 
fitted  on  to  the  other  side  of  the  pattern  to  form 


Fi-r-  10.  Fig.  11. 

Fijrs.    10   and    11.— Left-hand  Fork    End.      Fig.    12.— Top 

Member  of  Left-hand    Fork  End.     Fig.  13.  -Back    Stay 

Eye.     Fig.   14.— Front  Fork  End. 

the  right-hand  fork  end.  The  square  edges  of 
both  outside  and  inside  slots  should  be  chamfered 
off  to  leave  the  sand,  also  the  centre  of  the  D 
parts  where  it  is  hollowed  out. 

Top  Stay  Eye. — The  top  stay  eye  is  shown  at 
Fig.  13.  It  is  of  D-section,  and  of  the  same 
dimensions  as  the  top  part  of  the  fork  end  (see 
Fig.  12).  The  round  end  is  f  in.  by  T3(T  in.  thick, 
with  the  hole  f  in.  finished  sizes.  Two  of  these 


PATTERNS    FOR    FRAME    CASTINGS. 


23 


castings  will  be  required,  but,  being  exactly  alike, 
only  one  pattern  is  necessary. 

Front  Fork  Ends.— Two  front  fork  ends  (Fig. 
14)  will  be  required,  but  as  there  is  so  little  differ- 
ence in  their  construction,  one  pattern  may  be 
used  for  both.  The  only  difference  in  the  finished 
fork  ends  is  the  angle  of  the  two  projections 
with  the  flat  face ;  as  this  angle  is  so  small  (about 


Fig.  16. 
Figs.  15  and  16.— Patterns  for  Top  and  Bottom  Head  Lugs. 

3  or  4  degrees),  it  can  be  obtained  by  making  the 
pattern  with  no  angle  and  bending  the  casting  to 
suit.  The  pattern  may  be  cut  from  a  single 
piece.  The  flat  portion  (to  take  the  wheel  spin- 
dle) is  i  in.  thick,  the  f-in.  circular  portion,  which 
is  recessed  T\  in.  deep,  being  left  to  be  done  on  the 
casting.  The  slot  is  i  in.  wide,  but  it  will  be 
better  to  leave  this  part  solid,  and  either  saw  or 
file  out  the  slot  after  the  f-in.  hole  and  the  f-in. 


24  MOTOR    BICYCLE    BUILDING. 

recess  have  been  machined  in  the  casting.  The 
part  A  is  oval  in  shape,  f  in.  by  f  in.,  to  receive 
the  bottom  of  the  oval  front  fork;  and  the  round 
portion  B  is  f  in.  in  diameter,  to  receive  the 
lower  end  of  the  girder  tube.  The  angle  of  these 
two  lugs  will  be  best  obtained  from  the  full-size 
drawing. 

Top  and  Bottom  Head  Lugs. — The  top  and 
bottom  head  lugs  (Figs.  15  and  16)  are  very  simi- 
lar patterns,  the  only  difference  being  in  the 
angle  and  the  increased  length  of  the  bottom  lug. 
They  are  each  made  from  two  turned  parts,  glued 
and  pegged  together  at  the  angles  shown,  112 
degrees  for  the  top  lug  and  56  degrees  for  the 


Fig.  17.— Seat  Lug. 


Fig.  18.— Hear  Part 
of  Seat  Lug. 


bottom  lug.  Both  these  patterns  should  have  a 
core-box  to  get  the  cored  part  as  shown  by  the 
dotted  lines,  in  which  case  the  print  at  the  large 
end  would  be  l^f  in.  in  diameter  by  i  in.  long; 
this  would  be  allowing  ^  in.  for  finishing  the 
casting  to  1-|>-  in.  inside  at  the  end.  The  diameter 
of  the  prints  at  the  other  two  ends  is  lyL  in.  and 
l-j3^-  in.  by  i  in.  long.  If  it  is  decided  to  do  with- 
out core-boxes  for  these  two  patterns,  the  larger 
part  will  have  to  be  plain-cored  right  through 
lT3^in.,  leaving  the  recessed  portion  for  the  ball- 
race  to  be  machined  out  of  the  casting.  The 
diameter  of  the  print  for  the  lg-in.  tubes  is  the 
same  as  for  the  core-boxes,  but  the  length  is  differ- 
ent. The  core  being  supported  in  the  mould  at 


PATTERNS    FOR    FRAME    CASTINGS.  25 

one  end  only,   the  print  must  be  longer  on   the 

pattern   than   the   depth  to   be   cored.     Thus  the 

pvint  for  the  top  head  lug  should  be  l\  in.  long, 

//and  that  for  the  bottom  1|  in.  long. 

//       Seat  Lug. — The  seat  lug  (Fig.  17)  is  made  from 

/    two  turned  parts;  the  rear  part,  to  take  the  f-in. 

bolt,    is   cut   out   by   hand,    similar    in    shape   to 

Fig.    18,    and   glued    and   pegged   on.     Turn   the 

centre  part  for  the  down  tube  1T5^  in.  in  diameter 

in  the  centre,  tapering  to  1  -^  in.  at  each  end  by 

If  in.  long,  the  print  standing  out  i  in.  at  each 

end  by  lTV-in.  in  diameter.     The  front  portion  for 

the  top  tube  is  ly\-  in.  in  diameter  at  the  extreme 


Fig.  19. — Lower  Horizontal  Lug. 

edge,  tapering  up  at  about  3  degrees  of  taper.  The 
core-print  for  this  member  is  1T\  in.  in  diameter 
by  If  in.  long.  The  rear  part  is  cored  out  f  in., 
as  shown  by  the  dotted  lines  in  Fig.  18,  and  will 
require  a  print  of  this  diameter,  standing  out 
i  in.  at  each  end. 

Lower  Horizontal  Lugs. — The  patterns  for  the 
two  lower  horizontal  lugs  (Fig.  19)  are  alike 
except  in  the  angle,  the  one  shown  being  69  de- 
grees and  the  other  57  degrees.  They  are  made 
from  two  turned  parts,  and  each  member  is  to 
take  lg-in.  tube.  The  parts  are  exactly  as  the 
main  parts  of  the  seat  lug,  the  only  difference 


26  MOTOR    BICYCLE    BUILDING. 

being  the  absence  of  the  rear  ears  and  the  different 
angle  of  the  front  lug — that  is,  57  degrees.  The 
same  remarks  apply  with  regard  to  the  core- 
prints. 

Girder  Tube  Lugs. — Figs.  20  and  21  are  side 
and  top  views  of  one  of  the  girder  tube  lugs.  A 
pair  of  these  will  be  required,  but  the  difference 
is  so  slight  that  one  pattern  may  be  used  for  both. 
This  pattern  should  be  made  with  the  grain  of 
the  wood  running  with  the  length  of  the  pattern, 
and  the  prints  glued  and  pegged  on  each  side. 
The  drawings  give  all  dimensions,  which  are 


Figs.  20  and  21.— Girder  Tube  Lujrs. 

finished  sizes  of  the  machined  casting,  so  due 
allowance  must  be  made  for  machining.  The  core 
and  print  for  the  oval  part  should  be  made  as 
near  the  finished  size  as  possible,  as  this  has  to 
be  filed  out  in  the  casting.  It  will  be  necessary 
to  have  a  core-box  for  the  oval  part ;  a  piece  of 
fork  tube  of  this  size  and  section  will  answer  ad- 
mirably. The  length  of  prints  for  both  oval  and 
round  holes  need  be  only  J  in.  from  each  side  of 
the  pattern. 

Front  Fork  Crown. — The  pattern  for  the  front 
fork  crown  is  shown  in  top  and  front  view  by 


PATTERNS    FOR    FRAME    CASTINGS. 


27 


Figs.  22  and  23.  It  may  be  made  from  one  piece, 
with  the  prints  for  the  central  core  and  two  oval 
cores  glued  and  pegged  on.  It  is  4f  in.  over  all, 
If  in.  deep  at  the  ends,  where  the  forks  fit,  and 
1^  in.  deep  in  the  centre.  The  central  core-print 
is  lTVin.  in  diameter,  and  the  ovals,  indicated  by 
dotted  lines  in  Fig.  22,  Ij  in.  by  i£  in. ;  that  is 
the  full  finished  size,  and  owing  to  the  awkward- 
ness of  cleaning  out  these  in  the  casting,  it  will 
be  advisable  to  core  them  out  full  size,  or  very 


Figs.  22  and  23.— Front  Fork  Crown. 

nearly  full  size.  A  core-box  will  be  necessary  for 
this  pattern,  allowing  for  a  uniform  thickness  of 
£-  in.  in  the  casting,  as  shown  by  the  dotted  lines 
in  Fig.  23,  except  at  the  edges  of  the  oval  open- 
ings, which  may  be  a  bare  /a-  in.  It  will  be 
noticed  that  a  ring  or  collar  is  shown  on  top  of 
the  crown ;  this  is  for  the  bottom  ball-race  to  fit 
on.  The  core-prints  need  only  project  f  in.,  as 
the  core  will  be  supported  at  four  points. 

Ball-head    or   Steering    Tube   Lug.— The    ball- 


28 


MOTOR    BICYCLE    BUILDING. 


head,  or  steering  tube  lug,  is  shown  by  Figs.  24 
and  25,  these  being  side  and  bottom  views.  It  is 
made  by  turning  the  main  part  to  the  dimensions 
given,  allowing  for  machining.  The  central  core- 
print  is  ly^in.,  projecting  f  in.  at  each  end.  The 
rear  part  for  the  f-in.  bolt  is  cut  out  separately, 
and  glued  and  pegged  on.  It  is  l£  in.  wide,  and 
has  a  f-in.  core-print.  The  two  projections  to 


Fig.  25. 
Figs.  21  and  2o.— Steering  Tube  Lug. 

receive  the  ends  of  the  girder  tubes  are  cut  out 
to  shape  as  in  Fig.  25,  length  with  the  grain,  and 
the  two  lugs  turned  to  shape  and  glued  and  pegged 
on.  The  prints  are  y7^  in.  in  diameter  by  f  in. 
long.  The  two  projecting  pieces  being  so  light 
(only  T3(T  in.  thick),  they  should  be  dovetailed  into 
the  main  part  of  the  pattern,  as  well  as  glued  and 
pegged,  or  they  may  soon  be  broken  off  at  the 
foundry. 


PATTERNS    FOR    FRAME    CASTINGS. 


Engine  Plates. — The  pattern  for  the  engine 
plates  is  shown  by  Figs.  26  and  27,  which  are  side 
and  end  views.  Four  of  these  plates  will  be  re- 
quired. They  may  be  cast  in  malleable  iron  from 
a  pattern,  but  it  is  better  to  have  them  forged 
from  mild  steel.  Should  castings,  however,  ba 
used,  have  only  the  large  centre  hole  cored,  leav- 
ing the  ends  solid  to  be  drilled  out  in  the  casting. 


Fig.  20.  Fig.  27. 

Figs.  26  and  27.— Engine  Plate. 

This  also  applies'  if  forgings  are  used,  as  the 
exact  position  of.  these  holes  can  only  be  ascer- 
tained when  the  frame  is  built  and  the  engine 
tried  in  the  frame,  with  wheels  in  position. 

"  Leave  "  on  Patterns. — This  is  all  the  pattern- 
making  that  will  be  necessary,  and  it  only  re- 
mains to  get  the  required  number  of  castings  made 
from  them  at  a  good  malleable  iron  foundry.  All 
parts  of  the  patterns  must  be  nicely  smoothed  off 


30  MOTOK    BICYCLE    BUILDING. 

with  fine  glasspaper,  leaving  no  rough  edges  or 
parts,  and  care  must  be  observed  to  impart  suffi- 
cient "  leave  "  to  the  various  parts  requiring  it. 
What  is  meant  by  "  leave  "  on  a  pattern  will  be 
understood  by  taking,  first,  a  solid  ball  and  then 
a  solid  square  as  patterns.  The  ball  would  be 
moulded  half  in  each  moulding  box,  the  parting 
taking  place  exactly  at  the  centre  of  the  pattern ; 
thus,  as  all  parts  of  this  pattern  slope  away  from 
the  centre  or  parting  line,  no  "  leave  "  would  be 
necessary,  as  this  would  be  a  perfect  form  for 
leaving  the  sand  well.  But  if  a  solid  square  or 
cube  is  taken,  some  part  of  the  pattern  would 
have  to  be  tapered  off  to  enable  the  pattern  to 
come  away  from  the  sand  without  breaking  down 
some  part  of  the  impression,  unless  the  pattern 
was  moulded  with  a  corner  of  the  square  upper- 
most, and  the  parting  takes  place  at  a  point 
which  embraces  four  corners.  Whatever  other 
position  this  pattern  might  be  moulded  in,  some 
portions  of  the  flat  sides  would  have  to  be  tapered 
off  from  the  parting  line  to  enable  it  to  leave 
properly.  It  is  only  necessary  to  look  at  a  pat- 
tern carefully  and  imagine  which  will  be  the  most 
convenient  position  to  mould  it  in,  to  see  what 
parts  require  "  leave." 

Painting  Core-prints,  etc. — All  core-prints 
should  be  painted  black — a  little  vegetable 
black  mixed  with  varnish  will  do — and  the 
whole  pattern  given  two  coats  of  shellac 
varnish.  This  varnish  can  be  easily  made 
by  dissolving  brown  shellac  in  methylated 
spirit,  shaking  the  bottle  frequently.  Heat 
will  assist  it  to  dissolve,  but  great  care  must  be 
taken,  as  the  spirit  is  very  inflammable,  and 
likely  to  cause  an  accident  if  taken  too  near  a 
light.  The  inside  of  the  core-boxes  should  also 
be  given  two  good  coats  of  shellac  varnish  when 
finished. 

Making  Plain  Round  Cores. — For  making  the 


PATTEKNS    FOR    FRAME    CASTINGS.  31 

plain  round  cores,  nothing  beats  cycle  tube,  and 
pieces  of  this  to  fit  the  various  prints  should  be 
selected  and  cut  to  the  required  lengths.  Where 
the  junction  of  two  cores  is  at  an  angle,  such  as 
the  head  lugs,  seat  lug,  and  lower  horizontal  tube 
lugs,  the  core  tubes  should  be  cut  off  at  a  cor- 
responding angle,  and  also  hollowed  out  at  the 
angle  end,  so  that  the  coring  may  extend  as  far  as 
possible. 

Oval  Gores. — For  the  oval  cores  also  pieces  of 
fork  blade  of  the  proper  section  will  do  perfectly 
for  making  the  cores,  and  will  save  a  deal  of 
trouble  in  core-box  making. 

Dowelling  Halves  of  Gore-boxes. — The  two 
halves  of  the  core-boxes  for  fork  crowns,  or  what- 
ever core-boxes  that  are  made  in  halves,  should 
be  fitted  with  two  or  three  dowels  to  ensure  the 
halves  closing  perfectly  accurate ;  they  should  fit 
easily,  but  without  shake.  Small  brass  pegs  and 
sockets  can  be  purchased  for  the  purpose,  and 
where  the  boxes  are  likely  to  be  used  much  it  is 
advisable  to  fit  these,  as  the  wood  dowels  soon  wear 
with  much  usage. 

Metal  Patterns.— Where  a  large  number  of 
castings  are  to  be  made  from  one  pattern,  metal 
patterns,  preferably  brass,  are  made,  and  cast- 
iron  core-boxes  used. 

Dimensions  on  Illustrations.— It  must  be  borne 
in  mind  that  all  dimensions  given  in  the  illustra- 
tions included  in  this  chapter  are  finished  sizes 
of  castings,  and  due  allowance  must  be  made  for 
machining. 


CHAPTER  III. 

BUILDING    FRAME    FROM    CASTINGS. 

HAVING  received  the  castings  from  the  foundry, 
free  them  well  from  sand  ;  and  should  any  castings 
have  become  distorted  in  the  annealing  process, 
correct  this  by  careful  hammering. 

Bottom  Bracket. — The  bottom  bracket  may 
first  be  taken  in  hand.  Chuck  the  casting  in  a 
jaw  chuck,  and  bore  out  the  centre  part  ly7^  in.  in 
diameter,  leaving  f  in.  at  each  end  a  full  \^  in.  to 
screw  if  in.  by  24  threads.  Face  off  the  end 
standing  out  from  the  chuck  at  this  setting ;  the 
other  end  should  be  faced  off  on  a  screwed  mandrel 
to  get  perfect  truth ;  but  if  carefully  chucked,  it 
may  be  faced  fairly  true  by  this  means.  The 
bracket  cups  should  be  obtained  or  made  previous 
to  screwing  the  bracket,  so  that  they  may  be  tried 
in  to  fit  before  removing  the  casting  from  the 
chuck.  The  cups  should  be  a  good  tight  fit,  so 
that  they  can  only  just  be  screwed  up  with  a  peg 
wrench.  The  width  of  the  bracket  when  finished 
should  be  3^  in. 

Boring  the  Three  Tube  Lugs. — The  best  way  to 
bore  the  three  tube  lugs  will  be  on  an  angle  plate 
or  an  upright  drilling  machine  ;  but  if  such  a  tool 
is  not  available,  the  lathe  will  do,  either  by  bolt- 
ing the  angle  plate  to  the  face  plate,  or  by  hold- 
ing the  casting  in  the  jaw  chuck.  If  the  latter 
method  is  adopted,  greater  care  will  be  necessary 
in  seeing  that  the  holes  are  bored  at  perfect  right 
angles  to  the  centre  bore.  With  a  true  angle 
plate  and  the  ends  of  the  casting  faced  true,  this 
will  be  ensured.  The  front  member,  to  take  the 
tube  from  the  back  fork  crown,  will  be  bored  If 


BUILDING    FRAME    FROM    CARTINGS.  33 

in.  right  through  into  the  centre,  and  the  outside 
trued  up.  The  lug  to  take  the  down  tube  will  now 
be  bored  Ij  in.  right  through,  and  at  an  angle  of 
110  degrees  with  the  first  boring.  The  rear  lug 
is  bored  If  in.  at  an  angle  of  64  degrees  with  the 
last  boring.  The  various  tubes  should  be  tried  in 
their  places  before  the  casting  is  shifted,  and 
should  be  a  good  tight  push  fit  in  their  holes. 
Holes  for  lubricators  should  be  drilled  f  in.  from 
each  face,  in  such  a  position  that  the  lubricators 
will  be  upright  when  the  bracket  is  in  position. 
If  lugs  for  set  pins,  by  which  the  cups  or  discs  are 
to  be  locked,  have  been  provided,  these  should  be 
drilled  and  tapped  to  suit  the  set  pins.  The 
dimensions  of  the  disc  to  be  used  with  lock-nuts, 
and  also  of  the  bracket  axle,  will  be  given  later. 

Back  Fork  Crown. — The  back  fork  crown  cast- 
ing should  be  chucked  in  the  jaw  chuck  and  bored 
If  in.,  as  deep  as  possible,  and  the  edges  trued 
up  ;  or  the  ends  of  the  D-section  projections  may 
be  levelled  off  and  the  casting  stripped  to  the  face 
plate  to  bore  this  If  in.  hole.  Whichever  method 
is  adopted,  care  must  be  taken  to  get  the  hole 
perfectly  true  with  the  D  ends. 

Engine  Lugs. — The  engine  lugs  should  be 
chucked  true,  and  the  f-in.  holes  bored  right 
through  and  reamered,  the  faces  being  turned  up 
on  a  mandrel.  They  should  measure  3^  in.  over 
all  when  finished.  The  tube  lugs  should  then  be 
bored  ij  in.  and  If  in.  respectively,  and  the  edges 
trued  up. 

Front  Fork  Ends. — The  castings  of  the  front 
fork  ends  will  require  very  little  machining.  The 
f-iri.  hole  will  require  drilling,  and  the  f-in.  recess 
should  be  machined  in  the  outside  face  of  each 
with  a  peg  drill  or  cutter.  The  slot  can  then  be 
filed  out  to  meet  the  f-in.  hole.  The  f-in.  lug  to 
take  the  bottom  end  of  the  girder  tube  can  be 
turned  or  filed  as  preferred.  As  this  is  a  rather 
awkward  casting  to  chuck,  it  may  be  advisable  to 
c 


3i  MOTOR    BICYCLE    BUILDING. 

file  this  to  fit  the  tube  at  the  same  time  as  the 
oval  lug  is  filed  to  fit  the  lower  end  of  the  oval 
fork  blade.  Whilst  these  are  being  fitted  to  their 
respective  tubes,  they  should  be  tried  on  the  full- 
size  drawing  to  see  that  the  angle  is  correct.  The 
two  stay  eyes  will  require  drilling  out  f  in.  ;  these 
may  be  drilled  at  the  same  time  as  any  of  the 
other  |-in.  holes. 

Head  Lugs. — Chuck  the  head  -lugs  in  the  jaw 
chuck,  large  end  outwards  ;  bore  through  Ij  in. 
to  fit  the  head  tube,  and  turn  out  the  recess  fo,r 
ball-races,  as  shown  by  the  dotted  lines  in  Figs. 
15  and  16  (p.  23).  These  recesses  will  measure 
^\  in.  at  the  extreme  ends  by  —^  in.  deep.  Face 
off  the  ends,  and  true  up  the  outer  edges.  The 
Ij-in.  tube  members  may  be  bored  whilst  held  in 
the  jaw  chuck  or  on  the  angle  plate,  tilted  to  the 
correct  angle — 112  degrees  for  the  top  head  lug 
and  56  degrees  for  the  bottom  one. 

Seat  Lug.—  Chuck  the  seat-lug  casting  in  the 
jaw  chuck  to  bore  out  the  central  lj-in.  hole,  with 
the  top  end  outwards  ;  re-chuck  or  fix  on  the  angle 
plate,  to  bore  out  the  Ij-in.  hole  for  the  front 
tube.  The  rear  part  will  have  to  be  drilled  out 
|  in.,  and  ths  ears  faced  off  true  for  the  back-stay 
eyes  to  bed  against.  The  saw-cut  should  be  put  in 
the  back,  midway  between  the  ears,  before  the  lug 
is  fitted  and  brazed  to  the  seat  tube,  as  the  casting 
becomes  very  hard  and  difficult  to  saw  after  it  has 
been  brazed. 

Lower  Horizontal  Tube  Lugs. — The  treatment 
of  the  lower  horizontal  tube  lugs  is  the  same  as 
that  of  the  seat  lug ;  but  note  should  be  taken  of 
the  difference  in  the  angle. 

Drilling  Girder  Tube  Stays. — The  |-in.  hole  in 
each  of  the  girder  tube  stays  may  be  bored  on  the 
drilling  machine  or  the  lathe.  In  setting  these 
castings  for  boring  the  |-in.  hole,  due  allowance 
should  be  made  for  the  difference  in  parallel  be- 
tween this  and  the  oval  hole.  On  reference  to  the 


BUILDING    FRAME    FROM    CASTINGS  35 

full-size  drawing,  it  will  be  noticed  that  the  girder 
tubes  approach  nearer  to  the  centre  steering  line 
as  they  reach  the  top  of  the  head.  Also,  looking 
from  the  front  of  the  machine,  it  will  be  seen  that 
the  two  tubes  are  closer  together  at  the  top  than 
they  are  at  the  fork  crown.  If  this  difference  is 
allowed  for  when  drilling  the  f-in.  holes,  it  will 
not  be  necessary  to  bend  the  tubes  to  bring  them 
into  place.  Knocking  these  lugs  on  a  f-in.  man- 
drel, after  they  are  drilled  and  the  edges  trued  up 
in  the  lathe,  will  add  greatly  to  their  appearance. 
The  oval  holes  must  be  filed  out  to  fit  the  fork 
blades. 

Front  Fork  Crown. — The  front  fork  crown  may 
be  held  in  the  jaw  chuck  or  strapped  to  the  face- 
plate, the  centre  hole  bored  1|-  in.,  and  the  top 
faced  off  and  the  shoulder  turned  1^  in.  in 
diameter  by  |  in.  deep.  If  the  casting  is  being 
machined,  strapped  to  the  face-plate,  this  latter 
operation  will  have-  to  be  done  on  a  mandrel  be- 
tween the  centres.  The  oval-section  holes  will 
have  to  be  filed  or  scraped  out  for  the  fork  blades 
to  fit.  While  the  casting  is  on  the  mandrel  in  the 
lathe,  the  ends  of  the  ovals  may  be  faced  off  true. 

Steering-tube  Lug  Casting. — Chuck  the  steer- 
ing-tube lug  casting  bottom  or  large  end  outwards, 
bore  through  lj  in.  to  fit  the  steering  tube  (a  tight 
hand  fit),  and  recess  out  the  part  shown  dotted  in 
Figs.  24  and  25  (p.  28)  to  take  the  ball-race. 
This  will  be  of  the  same  size  across  as  the  recesses 
in  the  head  lugs,  but  ¥V  in.  deeper,  so  that  the 
edge  of  the-  casting  may  overlap  the  outer  edge 
of  the  top  ball  head  lug  when  the  two  are  brought 
together  with  the  balls  in  place.  This  hides  the 
balls,  and  keeps  the  bearing  more  or  less  dust- 
proof.  The  bottom  ball  head  lug  should  be  made 
to  overlap  the  bottom  ball-race  on  the  fork  crown 
in  the  same  manner  for  the  same  purpose.  At 
this  chucking,  the  under  side  of  the  front  ears 
may  be  faced,  as  well  as  the  edges  of  the  two 


36  MOTOR    BICYCLE    BUILDING. 

girder  tube  lugs,  on  a  mandrel  in  the  lathe 
centres  ;  the  outside  and  top  of  the  casting  may 
be  turned  up,  or  as  much  of  the  outside  as  the 
projections  will  allow.  The  ears  should  be  drilled 
out  |  in.,  and  faced  on  both  sides  with  a  facing 
cutter ;  the  cutter  that  was  used  for  recessing  the 
front  fork  ends  will  do  for  this  also.  The  two 
^-in.  holes  for  the  girder  tubes  must  now  be 
drilled,  and  finished  out  with  a  bottoming  drill 
or  cutter,  so  that  the  holes  have  square  corners  or 
a  flat  bottom.  A  fine  saw-cut  should  be  made 
nearly  half  through  the  casting,  just  under  the 
ears,  as  shown  in  Fig.  24  (p.  28),  and  a  broader 
cut  should  be  run  down  to  meet  this  midway  be- 
tween the  ears. 

Engine  Plates. — The  four  engine-plate  castings 
should  be  levelled,  the  |-in.  holes  drilled  square 
with  the  face,  the  sides  smoothed,  and  the  edges 
filed  up.  One  of  the  |-in.  holes  in  each  plate  may 
be  marked  off  and  drilled,  leaving  the  other  |-in. 
holes  to  be  marked  off  and  drilled  after  the  frame 
is  built  up  and  the  engine  is  in  position. 

Ball-races. — It  will  now  be  necessary  to  make 
the  ball-races  (Figs.  28  and  29,  p.  37).  Four  of 
these  will  be  required — three,  as  illustrated,  for  the 
steering  tube  lug  and  the  top  and  bottom  head 
lugs,  and  one  for  the  fork  crown  ;  this  last  will 
have  square  corners  instead  of  round,  and  a  lyV 
in.  hole  to  fit  the  shoulder  on  the  fork  crown,  the 
outside  diameter  being  1^4  in.  These  are  rather 
awkward  to  make  in  an  ordinary  lathe  ;  to  get 
them  true  they  are  made  on  a  large  hollow  mandrel 
lathe  from  the  bar.  It  would  be  as  well  to  buy 
these  ready-made,  as  they  do  not  cost  much.  If 
it  is  decided  to  make  them,  good  mild  steel,  well 
case-hardened,  should  be  used.  It  would  be 
simpler,  in  making  the  steering  bearings,  to  dis- 
pense with  cups  or  loose  ball-races  altogether,  and 
turn  the  ball-races  in  the  head  and  steering  lugs 
themselves,  with  a  steel  cone  only  to  fit  on  the  fork 


BUILDING  FKAME  FROM  CASTINGS.        sf 

crown.  In  this  case  the  bearings  should  be  two- 
point  bearings,  and  not  four-point,  as  shown  with 
the  loose  ball-races.  These  parts  will  not  bo  so 
durable  as  well-hardened  steel  ball-races  ;  but  if 
balls  not  less  than  ^'V  in.,  or  T3(I  in.  for  the  top  bear- 
ing and  -^L  in.  for  the  bottom  bearing,  are  used, 
they  will  wear  very  well.  The  malleable-iron 
castings  become  very  hard  when  they  are  brazed, 
and  thus  stand  a  lot  of  wear.  The  loose  steel 
cone  on  the  head  will,  of  course,  be  well  hardened, 
and  the  radius  of  the  bearing  curves  should  not 
be  much  greater  than  the  radius  of  the  ball  used, 
thus  giving  a  good  large  bearing  surface,  instead 
of  the  small  bearing  surface  usual  with  V-groove 


Fig.  28.      Fig  29. 
Figs.  28  and  29.— BalJ-race. 

bearing  discs.  One  advantage  of  the  absence  of 
loose  ball-race  bearings  is  that  there  are  no  separ- 
ate parts  to  gst  loose  and  cause  play  in  the  head 
Bottom  Bracket  Axle. — Fig.  30  gives  the  full 
dimensions  for  the  bottom  bracket  axle,  which 
should  be  made,  preferably,  from  one  of  Lead- 
beater  &;  Scott's  patent  stampings.  These  have 
a  dead  soft  centre,  which  will  not  harden,  with  an 
exterior  covering  of  a  carbon  steel  that  will 
harden  direct  in  water,  and  gives  a  very  hard 
wearing  surface.  Failing  one  of  these-  stampings, 
cast  steel  should  be  used,  carefully  hardened  at- 
the  wearing  parts  only.  Mild  steel,  case-hard- 
ened, does  very  well  for  this  job  if  proper  facilities, 
are  at  hand  for  pot-hardening ;  but  using  mild 


3S 


MOTOR    BICYCLE    BUILDING. 


steel,  and  attempting  to  harden  by  the  ordinary 
means  on  the  open  hearth  with  potash,  etc.,  is 
quite  useless.  In  making  this  axle,  cut  off  the  steel 
or  stamping  just  the  dead  lengths  required  before 
drilling  up  the  ends,  so  that  the  centres  upon 
which  the  axle  is  turned  may  be  left  in,  to  true  it 
up  by  after  hardening.  Fit  the  cranks  and  file  the 
keyways  before  hardening.  Special  wide  bracket 
discs  are  used  with  this  axle,  as  shown  at  A,  lock- 
nuts  (Figs.  31  and  32)  securing  them.  If  it  has 
been  decided  to  lock  these  discs  by  set  pins  or 
transverse  cotters,  the  ordinary  standard  pattern 
discs,  which  can  be  purchased  for  about  6d.  each, 
will  do.  Should  lock-nuts  for  the  bracket  discs  be 


Fig.  30. — Bottom  Bracket  Axle  in  Position. 

necessary,  they  may  be  made  from  ordinary  gas 
back-nuts,  bored  out  and  re-screwed,  if  suitable 
stampings  are  not  available  ;  or,  if  the  latter  are 
used,  they  can  be  made  from  stout  1-in.  washers, 
bored  and  screwed.  They  need  not  be  filed  up  or 
shaped  hexagon ;  but  a  couple  of  deep  notches 
may  be  filed  in  their  edge  for  adjustment  pur- 
poses, as  shown  in  Figs.  31  and  32.  They  should 
be  If  in.  by  24  threads,  the  same  as  the  discs, 
but  must  be  a  somewhat  easier  fit  on  the  discs 
than  the  discs  are  in  the  bracket,  otherwise  diffi- 
culty will  be  experienced  in  adjusting  the  bearing 
properly.  At  least  one  face  of  the  nuts  must  be 
trued  up  with  the  thread. 

Fitting  Lock-nut  to  Steering  Tube. — The  steer- 


BUILDING    FRAME    FROM    CASTINGS.          39 

ing  tube  must  be  screwed  at  one  end  with  a  fine 
thread  for  |  in.  down.  A  coarser  thread  than  26 
to  the  inch  should  not  be  used,  otherwise  the  tube 
would  be  weakened  by  the  depth  of  the  thread. 
A  lock-nut  to  fit  this  will  be  required,  and  the  re- 
marks made  with  reference  to  the  bracket  lock- 
nuts  applj7  also  to  this.  Whilst  screwing  the  steer- 
ing tube  and  fitting  the  nut,  pay  attention  to  the 
fitting  of  the  steering-tube  lug,  which  must  be  a 
good  sliding  fit  without  shake.  The  saw-cut, 
which  allows  the-  tube  to  be  tightened  on  to  the 


Fig-.  32. 


Figs.  31  and  32.— Bracket  Lock-nut, 


handle-bar  stem,  should  not  be  made  until  the 
handle-bar  has  been  fitted  in  the  tube. 

Engine  Bolts. — Two  f-in.  turned  engine  bolts 
(Fig.  33)  will  be  required  for  securing  the  engine 
plates  to  their  lugs.  These  are  turned  from  li-in. 
mild  steel,  one  to  the  dimensions  given  in  the 
illustration,  and  the  other  \  in.  shorter.  They 
should  be  a,  good  push  fit,  without  shake,  in  the 
f-in.  holes  of  the  engine  plates  and  the  lugs  on  the 
frame. 

Building  up  Frame. — All  the  lugs  and  parts 
having  been  machined  ready  for  fitting  up  to  the 
various  tubes,  the  rear  part  of  the  frame  may 
now  be  built  up.  Cut  off  the  back  forks  to  the 


40  MOTOR    BICYCLE    BUILDING. 

exact  length  required ;  clean  out  the  ends  where 
the  fork  ends  and  fork  crown  ends  fit ;  level  off 
the  ends  where  the  fork  ends  fit ;  and  chamfer 
off  the  inner  edge  of  the  D  tubes,  so  that  they  fit 
neatly  up  to  the  shoulders.  If  these  fit  tight, 
they  need  not  be  pegged  for  brazing.  Fit  the  top 
stay  eyes,  into  the  top  back  stays  in  a  similar  way. 
Cut  a  small  notch  in  the  bottom  of  the  f-in.  hole 
in  one  of  these  stay  eyes,  so  that  a  small  peg 
fitted  under  the  head  of  the  bolt,  which  holds  the 
seat  pillar  tight,  may  engage  with  this  slot  and  so 
prevent  the  bolt  from  turning  while  the  nut  is  being 
tightened  or  undone.  Before  fitting  up  the  fork 
ends  and  stay  eyes,  or  cutting  the  tubes  at  all,  see 
that  the  cranked  portion  of  these  comes  in  the 
proper  position  to  allow  of  the  belt  rim  clearing 
properly,  and  on  the  left-hand  side  of  the  machine. 
These  four  joints  are  then  brazed  and  filed  up. 

Setting  Rear  Fork  Ends.— The  fork  ends 
should  now  be  set  on  the  wheel.  (The  wheels 
should  be  made  or  procured  before  starting  to 
build  the  frame.)  To  set  the  fork  ends,  tighten 
up  in  their  place  on  the  wheel  spindle  and  set 
until  the  other  ends  of  the  forks  are  the  proper 
distance  apart,  to  correspond  with  the  D-section 
ends  of  the  fork  crown,  and  at  an  equal  distance 
from  the  edge  of  the  whe-el  rim.  It  is  better  not 
to  set  these*  in  their  place  on  the  spindle,  or  the 
latter  may  get  bent  with  the  strain  ;  they  should 
be  removed  to  the  vice  to  be  bent  to  the  required 
angle. 

Brazing  Tubes  to  Bottom  Bracket. — The  two 
short  pieces  of  If-in.  tube  may  now  be  fitted  to 
the  bracket,  and  also  the  down  tub©,  after 
thoroughly  cleaning  out  the  various  lugs  and  the 
ends  of  the  tubes.  The  ends  of  the  If-in.  tube 
that  fit  into  the  bracket  should  be  hollowed  out, 
to  allow  of  the  tubes  fitting  well  up  into  the 
bracket.  The  back  fork  crown  is  then  fitted  to 
the  other  end  of  the  If-in.  tube.  Now  try  this 


BUILDING    FRAME    FROM    CASTINGS.          41 

part  on  the  working  drawing,  and  see  that  all 
the  measurements  and  the  angle  of  the  down  tube 
are  correct.  Before  pegging  these  joints  and  braz- 
ing up,  make  sure  of  the  following  points :  The 
down  tube  must  be  at  right  angles  to  the  bore 
of  the  bracket ;  test  this  with  a  steel  straightedge 
on  the  trued-up  faces.  See  that  the  back  fork 
crown  is  square  with  the  down  tube  ;  test  this  by 
placing  the-  straightedge  on  the  top  of  the  D-sec- 
tion  ears  and  sighting  it  from  the  back,  when  the 
straightedge  should  appear  at  right  angles  to  the 
down  tube.  Some  blacklead  mixed  with  oil  should 
be  rubbed  into  the  threaded  ends  of  the  bracket, 
and  also  into  the  tapped  lubricator  holes,  to  pre- 
vent the  brass  and  borax  adhering  to  these  parts. 


Fig.  33.— Engine  Plate  Bolt. 

These  four  joints  will  require  careful  brazing,  and 
a  good  blast  to  obtain  sufficient  heat.  The  best 
way  to  proceed  is  to  direct  the  blast  on  to  the 
heavy  portion  of  the  front  lug ;  get  this  well 
heated  up,  and  make  the  front  l|-in.  joint.  Now 
shift  the  flame  on  to  the  root  of  the  l^-in.  lug,  and 
braze  this  joint ;  then  on  to  the  heavy  part  of  the 
rear  l|-in.  lug,  and  finish  this  joint. 

It  will  be  advisable  next  to  remove  the  job 
from  the  hearth  and  thoroughly  brush  these  joints, 
while  well  hot,  with  the  wire  brazing  brush.  The 
joint  of  the  rear  If-in.  tube  with  the  back  fork 
crown  can  then  be  finally  brazed.  Brazing  this 
last  joint  will  scale  the  D  ends  of  the  crown,  and 
these  must  therefore  be  cleaned  up  again  before 
fitting  the  back  forks.  Small  air-holes  must  be 


42  MOTOR    BICYCLE    BUILDING 

drilled  on  the  inside  of  these  back  forks  before 
filing  up  and  brazing.  Other  tubes  requiring  air- 
holes for  brazing  will  be  the  back  stays,  lower 
horizontal  tube,  and  front  forks ;  and  the  top  tube 
and  bottom,  front  tube  as  well,  unless  the  ends  of 
these  are  opened  out  into  their  lugs.  When  the 
back  forks,  exactly  equal  in  length,  are  finally 
fitted  to  the  crown,  remove  and  load  each  tube 
with  brass  and  borax,  knock  the  joints  well  home, 
and  peg  securely.  Fix  a  stay  or  strut  between 
the  two  fork  ends,  so  that  they  will  be  held  the 
same  distance  apart  as  they  will  be  when  the 
wheel  is  in  position.  In  the  absence  of  a  suitable 
stay,  the  hub  spindle  will  do,  the  cones  and  nuts 
being  used  to  keep  the  fork  ends  the  correct  dis- 
tance apart  and  the  faces  square  with  each  other. 
Shake  the  charge,  placed  inside  the  tubes,  well 
down  towards  the  joints,  and  braze  one  at  a  time, 
with  the  fork  on  its  side. 

Fitting  Ball-head.— Fit  up  the  ball-head  tube 
to  the  top  and  bottom  head  lugs,  the  top  tube 
to  the  top  head  lug,  and  the  bottom  front  tube  to 
the  bottom  head  lug,  and  peg  the  joints.  The  ends 
of  the  tubes  should  be  hollowed  out  to  fit  up 
against  the  head  tube.  Before  brazing,  see  that 
the  three  tubes  are  in  one  plane  ;  to  test  this, 
place  a  long  straightedge  across  the  ends  of  the 
top  and  bottom  tubes,  and  sight  this  with  the  ball- 
head  tube.  Also  see  that  the  ends  of  the  tubes 
are  the  proper  distance  apart  to  drop  into  place 
with  the  seat  lug  and  front  engine  lug  on  the  draw- 
ing. While  these  joints  are  hot,  scrape  out  the 
ends  of  the  ball-head  lugs,  where  the  ball  races 
fit ;  this  will  save  a  lot  of  work  after,  if  any  brass 
has  stuck  to  these  parts.  Mark  off,  on  the  down 
and  bottom  tubes,  the  position  that  the  Ipwer 
horizontal  tube  lugs  will  occupy,  and  clean  the 
tubes  at  these  parts.  Slip  the  two  lugs  on  to  the 
down  and  bottom  tubes  before  the  seat  lug  or  the 
front  engine  lug  is  fitted  to  its  tube. 


BUILDING    FRAME    FROM    CASTINGS.  43 

Fitting  Front  to  Rear  Parts. — The  seat  lug 
can  now  be  fitted  to  the  top  tube,  and  the  lower 
horizontal  tube  to  its  lugs,  and  the  front  and  rear 
portions  of  the  frame  connected  together  by  fitting 
the  seat  lug  on  to  the  top  of  the  down  tube.  In 
fitting  this  front  portion  to  the  rear  part,  see 
that  all  the  tubes  lie  in  one  plane  before  pegging 
up.  To  test  this,  place  a  long  straightedge  across 
each  side  of  the  ball-head  and  down  tubes ;  the  end 
of  this  should  fall  at  an  equal  distance  from  each 
fork-end  face.  The  ball-head  tube  must  also  be 
perfectly  parallel  with  the  down  tube. 

These  three  joints  may  now  be  brazed  up.  The 
top  tube  is  opened  out  into  the  seat  lug  by  punch- 
ing a  hole  through  the  down  tube  inside  the  seat 
lug.  This  will  act  as  an  air  hole,  and  serve  as  a 
means  of  feeding  a  charge  of  brass  and  borax 
to  the  joint.  The  lower  horizontal  tube  lug  joints 
may  be  fed  by  ramming  a  piece  of  paper  down  the 
tube,  about  the  centre,  before  fitting  up ;  a  charge 
can  then  be  inserted  at  each  end  of  the  tube,  the 
paper  keeping  them  apart. 

Fitting  Top  Back  Stays. — The  top  back  stays 
may  now  be  fitted  and  brazed  up.  Before  pegging 
up  these  two  joints,  the  wheel  must  be  tried  in 
place,  and  the  stays  so  fitted  that  the  rim  of  the 
wheel  is  exactly  central  between  them.  Fit  the 
mud-guard  stay,  and  braze  in  place,  to  give  1^-in. 
clearance  between  the  mudguard  and  the  tyre. 
The  fitting  and  brazing  of  the  engine  lugs  had 
better  be  left  until  the  front  forks  are  built  and 
the  engine  is  ready. 

Fitting  Front  Forks. — Now  the  front  forks 
may  be  secured.  Fit  and  braze  the  steering  tube 
to  the  fork  crown ;  then  square  off  the  bottom  ends 
of  the  front  forks  and  clean  out  all  scale,  and 
serve  the  lower  ends  of  the  girder  tubes  in  the 
same  way.  Fit  the  fork  ends  to  the  fork  blades, 
set  in  the  same  manner  as  the  rear  fork  ends  on 
the  front  wheel,  and  braze  up  these  two  joints. 


44  MOTOR    BICYCLE    BUILDING. 

Next  cut  off  the  top  ends  of  the  blades  to  the 
proper  length,  to  give  the  required  clearance  to 
the  tyre  under  the  fork  crown.  Clean  the  ends 
of  the  blades  outside  sufficiently  far  down  to 
allow  for  the  girder  tube  stays,  then  slip  these 
stays  on  over  the  fork  blades,  load  each  with 
brass  and  borax,  and  fit  into  the  crown,  taking 
care  to  knock  them  well  home.  The  two  blades 
should  be  of  exactly  the  same  length,  and,  after 
being  tested,  should  be  fixed  at  an  equal  angle 
to  the  steering  tube  when  the  ends  are  the  proper 
distance  apart.  Fit  the  wheel  in  the  forks,  and 
see  that  the  rim  is  central  between  them,  and  use 
the  straightedge  to  see  that  the  steering  tube  is 
true  with  the  wheel  rim.  When  this  is  all  as- 
sured, fix  the  wheel  spindle  or  other  stay  between 
the  fork  ends,  and  peg  and  braze  up  the  four 
joints. 

The  f-in.  holes  of  the  girder  tube  stays  must 
now  be  cleaned  out,  the  tubes  where  they  fit  these, 
and  the  inside  of  the  lower  ends,  to  fit  on  the 
front  lug  of  the  fork  ends.  The  exact  length  of 
these  two  girder  tubes  is  obtained  by  assembling 
the  ball-head  with  balls  and  races  in  position. 
It  is  very  important  that  the  length  of  these 
shall  be  absolutely  exact,  for  if  they  are  the  least 
bit  too  long,  the  ends  would  bottom  in  the  holes  of 
the  lugs  on  front  of  the  steering-tube  lug  before  the 
bearing  was  properly  adjusted.  The  tubes  should 
be  of  such  a  length  as  to  be  about  ~  in.  off  the 
bottom  of  the  holes,  when  the  bearing  is  tightly 
adjusted.  This  allows  for  subsequent  wear  and 
adjustment  of  the  head  bearings.  Of  course,  it- 
is  understood  that  the  tops  of  these  tubes  are  not 
brazed  into  the  lugs,  but  are  a  good  tight  sliding  fit 
in  them.  When  the  proper  length  has  been  obtained, 
take  down  the  head  and  braze  the  four  joints  at 
the  crown  and  lower  ends.  It  will  be  as  well  to 
slip  the  steering  tube  lug  on  to  the  top  ends  of 
the  girder  tubes  while  these  four  joints  are  being 


BUILDING    FRAME    FROM    CASTINGS.  45 

brazed,  thus  ensuring  them  being  the  exact  dis- 
tance apart  to  drop  afterwards  into  their  places. 

Before  filing  up  the  fork  joints*  try  the  front 
wheel  again,  to  see  if  any  part  has  sprung  or 
given,  and  thus  thrown  the  wheel  out  of  centre. 
It  will,  of  course,  be  better  to  correct  this  now 
than  to  wait  until  after  the  joints  are  filed  up. 
While  the  wheel  is  in  the  fork,  both  before  and 
after  brazing,  place  the  straightedge  across  the 
front  of  the  fork  crown,  and  see  that  is  is  parallel 
with  the  wheel  spindle.  Should  the  fork  be  on 
the  twist,  this  can  be  rectified  by  holding  the 
crown  in  the  vice  and  inserting  a  bar  between  the 
lower  end  of  the  fork  blades. 

Handle-bar  and  Seat  Pillar.— The  handle-bar 
and  seat  pillar  call  for  no  special  mention,  ex- 
cept that  they  are  stronger  than  the  ordinary 
cycle  type,  and  that  the  handle-bar  is  wider  and 
longer,  as  already  mentioned.  The  stem  of  both 
the  seat  pillar  and  the  handle-bar  should  be  fitted 
into  their  respective  tubes  before  the  saw-cut  is 
made  down  them. 

Fitting  Engine  Plates. — If  the  engine,  or  the 
crank  case  of  the  engine,  is  now  available,  the 
four  engine  plates  can  be  fitted  to  the  crank  case. 
The  pair  on  the  pulley  side  will  be  let  in  flush 
with  the  surface  of  the  crank  case,  so  as  to  give 
clearance  to  the  belt.  With  the  engine  lugs 
slipped  on  to  the  ends  of  the  bottom  down  tube 
and  the  short  l-§-in.  tube,  the  proper  position  for 
the  f-in.  holes  in  the  engine  plates  and  the  correct 
position  of  the  engine  lugs  on  the  tubes  can  be 
marked  off  to  bring  the  engine  square  and  per- 
pendicular in  the  frame.  The  two  lugs  should 
be  pegged  on  the  tubes  while  the  crank  case  and 
plates  are  in  position  with  alj  bolts  in,  to  ensure 
their  coming  together  again  properly  when  brazed 
up.  It  will  be  advisable  to  blacklead  the  inside 
of  the  f-in.  holes  in  the  engine  lugs  before  brazing 
to  prevent  them  scaling  or  getting  brass  on  them. 


46  MOTOR    BICYCLE    BUILDING. 

Final  Setting  of  the  Frame. — The  final  setting 
of  the  frame  should  be  done  now.  Put  the  bracket 
axle,  discs,  and  balls  together  in  the  bracket,  and, 
with  the  chain  wheel  and  the  crank  fixed  in 
position  and  the  back  wheel  in  the  forks,  line  up 
the  two  chain  wheels  with  a  straightedge.  With 
the  straightedge  on  the  outer  face  of  the  bracket 
wheel,  the  other  end  should  just  fall  clear  of  the 
chain-wheel  face  on  the  back  hub. 

The  front  wheel  and  fork  can  now  be  fitted 
up  in  the  frame,  and  the  two  wheels  tested  for 
being  in  track  or  in  line.  A  long  straightedge 
should  be  placed  on  the  sides  of  the  back  wheel 
rim,  and  tested  with  the  sides  of  the  front  rim. 
This  will  be  done  with  the  machine  upside  down. 
When  this  is  set  satisfactorily,  place  the  machine 
right  end  up,  and,  with  the  straightedge  on  the 
face  of  the  rim,  see  that  the  front  fork  tube  is 
upright  with  the  back  wheel.  This  is  done  more 
easily  if  a  piece  of  tube  or  a  long  mandrel  is  fitted 
into  the  steering  tube. 

The  frame,  etc.,  may  now  be  filed  up,  and  sent 
out  to  be  enamelled  and  plated. 


47 


CHAPTER    IV. 

MAKING    A    3i-H.P.     PETROL    MOTOR. 

THE  motor  to  be  described  in  this  chapter  will 
develop  3i  h.p.,  and  is  suitable  for  the  frame 
described  in  the  previous  chapters.  It  is  quite 
powerful  enough  for  use  with  a  trailer,  side,  or 
fore  car.  With  a  two-speed  gear,  it  may  also  be 
used  for  a  tri-car.  This  is  not  an  experimental 
engine,  but  one  that  has  been  made  and  well  tried 
over  some  thousands  of  miles,  giving  every  satis- 
faction. It  is  of  original  design  and  simply  con- 
structed with  as  few  parts  as  possible  (see  the 
vertical  'section,  Fig.  34,  in  which  the  valve 
springs  are  not  shown).  The  patterns  for  all  the 
parts  are  finished,  and  are  available  to  readers  of 
this  handbook  who  would  like  to  purchase  the 
castings  instead  of  making  their  own  patterns, 
so  that  an  immediate  start  could  be  made.  The 
cylinder  pattern  is  an  exceedingly  difficult  one 
for  an  amateur  to  make ;  in  fact,  it  is  the  work  of 
a  first-class  pattern-maker  to  turn  out  a  good 
working  pattern. 

Fig.  35  is  a  section  of  the  cylinder  through  the 
line  x  x  in  Fig.  36,  which  is  a  plan  of  the  top. 
Fig.  37  is  a  plan  of  the  bottom  or  open  end  of  the 
cylinder. 

Boring  Cylinder. — The  first  and  most  im- 
portant part  to  be  taken  in  hand  is  the  cylinder. 
The  boring  and  machining  of  this  calls  for  the 
greatest  care  and  skill  to  obtain  really  good  re- 
sults. The  cylinder,  etc.,  being  all  in  one  cast- 
ing, increases  the  difficulty  of  accurate  boring, 
but  makes  a  much  more  satisfactory  job  when 
finished.  Before  starting  the  boring  operation, 
the  casting  should  be  carefully  examined  for 


MOTOR    BICYCLE    BUILDING. 


Fig.  34.— Vertical  Section  of  3|-h.p.  Petrol  Engine. 


MAKING  A  3A-H.P.  PETROL  MOTOR. 


4<J 


blow  holes  or  faulty  places,  especially  in  the  bore 
and  valve  seats.  All  sand  should  be  thoroughly 
scraped  out,  and  any  rough  projections  filed  or 


Fig.  86. 


-IX 


f 

^ 314I- * 

Figs.  35  and  36. — "Vertical  Section  and  Plan  of  Engine 

Cylinder. 
D 


50  MOTOR    BICYCLE    BUILDING. 

carefully  chipped 'off.  The  open  end  should  be 
filed  level,  and  a  piece  of  hardwood  fixed  across 
the  open  end.  From  a  centre  marjked  on  this 
hardwood  the  size  of  bore  can  be  scribed  off  and 
lightly  centre-dotted.  The  bore  is  82  mm.,  or 
approximately  ^T  in.  under  3£  in. ;  and  the  stroke 
is  3^  in.  In  outlining  the  bore,  it  is  advisable 
to  mark  just  outside  the  exact  bore,  so  that  the 
boring  will  not  completely  obliterate  the  marks. 
There  is  a  small  boss  on  the  top  of  the  cylinder; 
this  boss  is  perfectly  central  with  the  cylinder 
walls,  and  is  placed  there  to  assist  in  setting  the 
casting  true  for  boring,  and  to  take  the  centre 
for  turning  up  the  outside  below  the  radiators. 
The  boss  should  be  carefully  centred,  and  drilled 
up  with  a  small  hole,  and  countersunk  to  the  same 
angle  as  the  lathe  centres.  Another  use  for  this 
boss  is  to  time  the  valves,  by  passing  a  wire  down 
a  hole  drilled  right  through  and  afterwards 
stopped  up  with  a  small  screw. 

The  casting  may  be  strapped  to  the  face  plate, 
and  bored  up  with  a  tool  in  the  slide-rest  or 
strapped  down  to  the  saddle  and  bored  with  a 
stiff  boring  bar  held  in  a  firm,  solid  chuck.  By 
the  first  method,  cylinders  may  sometimes  be 
bored  accurately,  but  the  chances  are  against  it. 
The  latter  method  will  be  more  satisfactory.  A 
good  stiff  boring  bar,  not  less  than  li  in.  in 
diameter  and  no  longer  than  absolutely  neces- 
sary, should  be  used.  This  should  be  fitted  with 
a  flat  cutter  made  from  l|-in.  by  j-in.  steel,  double 
cutting,  the  corners  being  rounded  off  and  the 
cutting  edges  slightly  backed  off.  Three  cutters 
are  required,  a  roughing,  second,  and  finishing, 
the  last  being  only  slightly  rounded  on  the  corners 
and  the  cutting  edges  finely  finished  off  on  the  oil- 
stone to  the  size  of  the  bore — that  is,  82  mm. 

The  cutter  must  run  dead  true  in  the  lathe, 
or  the  bore  will  be  greater  than  the  width  of  the 
cutter.  Three  cuts  should  be  sufficient,  the  finish- 


MAKING    A    3i-H.P.    PETROL    MOTOR. 


ol 


ing  one  being  a  mere  scrape.  During  the  finishing 
cut  and  the  one  before  it,  the  lathe  must  not  be 
stopped  from  the  commencement  to  the  finish  of 
the  cut.  The  job  may  be  done  with  one  cutter, 
one  end  only  cutting,  and  the  cutter  adjusted 
farther  out  for  each  cut;  but  it  should  be  freshly 
sharpened  for  the  finishing  cut.  A  single-ended 
cutter  is  more  liable  to  spring  and  follow  in- 
equalities in  the  casting  than  a  double-ended 
one,  and  for  this  reason  at  least  one  extra  cut 
should  be  employed  in  the  operation. 

The   casting  must  be  very  carefully  set,   and 


Fig.  37.— Plan  of  Bottom  or  Open  End  of  Cylinder. 

bolted  down  with  good  broad  straps,  one  strap 
coming  across  the  thick  part  of  the  valve  cham- 
ber and  the  other  across  the  flange  at  the  bottom. 
Secured  in  this  manner  the  casting  is  less  liable 
to  be  sprung  out  of  shape.  The  cylinder  walls 
being  only  ^\  in.  thick  (finished),  no  allowance 
can  be  made  for  any  inaccuracy  in  setting.  The 
small  lug  on  top  of  the  cylinder  will  here  be  found 
useful,  as  the  back  centre  of  the  lathe  can  be 
brought  up  close  to  the  casting  and  used  to  test 
the  accuracy  of  this  end ;  the  open  end,  of  course, 
can  be  more  easily  set  by  the  cutter  edges. 

The  cutter  slot  in  the  boring  bar  should  be 
within  -4  in.  of  the  end,  to  avoid  any  risk  of  the 
end  of  the  bar  coming  in  contact  with  the  cylinder 


62  MOTOR    BICYCLE    BUILDING. 

end  and  thus  shifting  the  setting;  this  would  be 
disastrous  in  the  finishing  cut  or  the  one  before 
it.  It  will  be  noticed  that  the  last  f  in.  of 
tne  cylinder  is  shown  counter-bored.  It  will  not 
be  necessary  to  bore  this  part  if  the  casting  is 
accurately  set,  as  the  casting  is  cored  out  at  this 
part  y1^  in.  larger  than  the  finished  bore. 

Machining  Chamfer  at  Mouth  of  Cylinder. — 
At  this  setting,  after  the  bore  is  finished,  the 
chamfer  at  the  mouth  of  the  cylinder  should  be 
machined.  This  can  be  done  with  a  separate 
cutter,  or  a  corner  of  the  back  portion  of  on-e  used 
for  boring  may  be  filed  to  the  necessary  shape. 
This  chamfer  is  necessary  for  the  easy  insertion 
of  the  piston  when  the-  rings  are  in  position.  The 
extreme  end  may  also  be  trued  up  with  the  cutter 
at  this  setting.  This  should  be  done  to  allow  of 
the  under  part  of  the  flange  being  -^  in.  from  the 
end  and  the  cylinder  6|  in.  deep.  To  machine  the 
valve  chamber,  the  casting  should  be  firmly  bolted 
down  to  a  perfectly  true  face  plate,  2|  in.  out  of 
the  centre,  to  get  the  opening  true.  As  the  sur- 
face in  contact  with  the  face-  plate  is  so  small,  the 
casting  is  liable  to  shift  during  machining  unless 
it  is  very  firmly  bolted  down.  A  sheet  of  brown 
paper  placed  between  the  face  plate  and  the  mouth 
of  the  casting  will  greatly  assist  in  keeping  it  from 
shifting. 

Valve  Seating,  Opening,  etc. — When  set  true, 
bore  out  and  screw  the  exhaust-valve  guide  holes 
A  (Fig.  35)  to  f-in.  whitworth.  With  a  hook  tool, 
face  the  under  side  of  this  hole  for  the  collar  on 
the  guide  to  bed  true  against ;  this  collar  will  be 
1TV  in.  in  diameter.  The  seating  for  the  exhaust 
valve  will  be  bored  out  If  in.,  the  upper  side  being 
•chamfered  as  shown  and  the  top  trued  up.  The 
opening  for  the  inlet  valve  is  bored  out  lj  in.,  and 
chamfered  the  same  as  the  exhaust  opening ;  \  in. 
above  this  bore  out  If  in.  ;  the  remaining  portion 
"B  (|  in.)  is  bored  1T^  in.  bare,  and  screwed  20 


MAKING    A    3A-II.P.    PETROL    MOTOR.  53 

threads  to  the  inch,  which  will  make  it  If  in.  at  the 
bottom  of  the  thread.  Face  off  the  top  of  the 
opening  true  to  the  dimensions  given. 

Turning  up  Outside  of  Cylinder. — To  turn  up 
the  outside  of  the  cylinder  below  the  radiators, 
the  casting  should  be  run  on  the  centres.  For 
this,  a  large  centre  to  fit  the  back  poppet  of  the 
lathe  must  be  made,  or  the  mouth  of  the  cylinder 
may  be  bridged  with  a  stout  piece  of  iron  or  steel 
carefully  fitted  to  the  bore  and  centred  true.  The 
outside  between  the  lower  radiator  and  the  top  of 
the  flange  is  turned  to  3T7^in.,  the  flange  being  left 
$  in.  thick,  and  the  shoulder  3j  in.  in  diameter  by 
-j^  in.  deep  ;  this  shoulder  should  be  left  with  a 
very  slight  taper  on  it,  so  that  it  may  fit  tight  into 
the  opening  in  the  top  of  the  crank  case. 

Opening  for  Exhaust  Pipe,  etc. — The  opening 
for  the  exhaust  pipe,  which  is  indicated  by  the 
dotted  circle  c  (Fig.  1)  in  the  centre  of  the  valve 
chamber,  must  now  be-  drilled  and  tapped.  This 
is  lj  in.  by  26  threads,  and  is  best  done  on  the 
drilling  machine,  using  a  suitable  tap  to  form  the 
thread,  as  it  is  rather  awkward  to  chuck  or  hold 
in  the  lathe.  The  sparking-plug  hole  D  is  drilled 
and  tapped  |~J  in.  by  17  threads,  and  is  faced  on 
the  outer  surface. 

Flange  on  Cylinder  Bottom. — The  flange  on 
the  cylinder  bottom  is  left  the  full  size  at  present, 
being  filed  off  flush  with  the  flange  on  the  top  of 
the  crank  case  after  the  two  parts  are  fitted  to- 
gether. 

Holes  for  Holding-down  Bolts. — The  four  f-in. 
holes  for  the  holding-down  bolts,  shown  in  the 
plan  of  the  bottom  end  at  Fig.  3,  should  be  drilled 
in  such  a  position  as  to  Leave  an  equal  amount  of 
metal  round  the  corresponding  holes  in  the  crank 
case,  but  keeping  the  holes  sufficiently  far  from  the 
outer  face  of  the  cylinder  to  enable  the  corners  of 
the  bolt  heads  to  clear  properly. 

Piston. — The    piston    casting    should    now    be 


54  MOTOR    BJCYCLE    BUILDING. 

trimmed  up  by  filing  or  carefully  chipping  off  all 
rough  projections  left  from  the  foundry.  The  cast- 
ing should  be  chucked  by  the  projection  left  on 
the  end  of  the  casting,  in  a  3-jaw  or  4-jaw  chuck, 
and  should  not  be  shifted  until  all  the  turned  work 
is  finished.  In  setting  the  casting,  true  up  from 
the  inside,  for  unless  the  inside  is  true  the  piston 
will  be  very  thin  on  one  side  when  finished,  as  the 
walls  will  be  rather  light  in  parts.  Turn  up  the 
outside  perfectly  parallel  from  end  to  end,  82  mm. 
in  diameter;  it  should  be  a  fairly  easy  fit  in  the 
cylinder  at  this  stage.  Turn  as  near  the  size  as 
possible  with  a  light  finishing  cut,  and  smooth  off 
to  the  final  fitting  with  a  dead  smooth  file.  True 
up  the  open  end,  and  with  a  good  sharp  parting 
tool  cut  down  the  head  to  the  projection  by  which 
the  casting  is  held,  leaving  it  3j  in.  long  from  end 
to  end. 

Ring  Grooves  in  Piston. — The  ring  grooves 
may  now  be  put  in  ;  these  are  y^-  in.  wide  by  |  in. 
deep,  and  are  g  in.  apart,  the  first  or  top  one 
starting  J  in.  from  the  end.  The  tool  with  which 
these'  are  cut  must  be  carefully  made  and  set,  so 
as  to  leave  the  sides  perfectly  square  and  the 
corners  sharp.  A  tool  made  as  a  parting  tool, 
jusb  yV  in-  wide,  with  the  sides  slightly  backed  off, 
will  do  the  job  at  one  cut,  and  ensure  them  being 
all  the  same  width  ;  but  unless  the  lathe  is  a  good 
solid  tool,  free  from  spring,  the  yV^n-  cu^  may  be 
too  much  for  it  and  set  up  chattering.  In  this 
case,  a  narrower  tool  must  be  made,  not  more 
than  g  in.  wide.  Whichever  way  the  job  is  done, 
the  sides  of  the  grooves  must  be  perfectly  parallel 
and  square.  A  small  sheet-metal  template  should 
be  filed  out  for  the  purpose  of  testing  them  for 
depth  and  width. 

Gudfjeon-pin  Hole. — At  a  distance  of  lj  in. 
from  the  top  end,  scribe  a  line  round  the  piston 
with  a  sharp-pointed  tool  held  in  the  slide-rest ;  on 
this  line  will  be  marked  off  the  centres  for  drill- 


MAKING    A    3i-H.P.    PETROL   MOTOR.  55 

ing  th-e  gudgeon-pin  hole.  If  the  lathe  is  provided 
with  a  dividing  plate,  the  centres  can  now  be 
easily  marked  off.  Otherwise,  mark  the  first 
centre  true  with  one  of  the  projections  on  the  in- 
side of  the  casting ;  the  other  centre  may  be 
found  with  the  dividers,  or  the  scribing  block  used 
on  the  lathe  bed.  It  will  be  noticed,  on  reference 
to  Figs.  38  and  39,  which  are  sections  of  the  fin- 
ished piston,  that  most  of  the  surface  between  the 
gudgeon-pin  hole  and  the  open  end  is  turned  down 


I. 


Fig.  38.— Section  of  Finished  Piston. 

a  shade  smaller  than  the  main  diameter.  This  is 
done  to  lessen  the  amount  of  frictional  surface 
in  contact  with  the  cylinder  walls,  to  lighten  it, 
and  to  help  lubrication.  The  oil  thrown  up  on  the 
inside  of  the  piston  finds  its  way  into  this  recessed 
part  through  the  holes  drilled  therein.  Another 
small  groove  at  the  extreme  end  is  cut  in  as  shown 
for  a  depth  of  -£-.T  in. 

Inside  of  Piston. — The  inside  may  now  be 
turned  up  as  far  as  possible,  leaving  the  walls 
J.J-  in.  thick  in  the  thinnest  part.  The  inside  should 
taper  slightly  as  shown,  to  within  ^  in.  of  the  ex- 
treme edge,  where  a  shoulder  is  left,  making  it 


56  MOTOR    BICYCLE    BUILDING. 

£  in.  thick  at  this  part.  The  smooth  file  should  be 
lightly  run  over  the  surface,  to  remove  any  rough 
edges  thrown  up  by  the  lathe  tools. 

Completing  the  Piston. — The  casting  can  now 
be  parted  off  from  the  projection  by  which  it  is 
held  in  the  chuck.  Care  should  be  taken  that  it 
does  not  drop  off  unexpectedly  at  the  finish  and 
chip  the  thin  end.  The  gudgeon-pin  hole  should 
be  drilled  bare  \  in.  and  reamered  out  to  full  ^  in., 
with  just  a  shade  of  taper  ;  mark  the  large  end 
with  a  centre-punch.  The  inside  faces  of  the  hole 
should  be  trued  up  with  a  facing  cutter.  When 
finished,  they  should  bs  2j  in.  apart,  with  both 
faces  the  same  distance  from  the  outer  surface. 
A  small  special  cutter  bar  will  be  required  for 
this  job.  Turn  down  5  in.  of  f-in.  or  T97y-in-  mild 
steel  to  nicely  fit  the  A-in.  hole;  then,  f  in.  from 
the  end,  cut  out  a  slot  i  in.  by  |  in.,  and  fit  a 
cutter  to  suit  this  slot  made  of  tool  steel  properly 
hardened.  The  bar  is  then  pushed  through  one 
side,  and  the  cutter  tapped  into  position  in  the 
bar.  The  cutter  bar  may  be  held  in  the  chuck, 
and  the  piston  supported  on  the  back  centre.  The 
end  of  the  cutter  bar  may  be  coned  out  with  the 
point  of  a  4-in.  or  f-in.  drill  for  a  short  distance  if 
there  is  any  likelihood  of  the  lathe  centre  meeting 
the  end  of  the  bar  before  the  cutter  has  done  its 
work.  Drill  about  twelve  J-in.  to  fV"1-  holes  in 
the  recessed  part  as  shown,  and  the  position  is 
complete. 

Lapping  Out  the  Cylinder. — In  the  absence  of 
a  proper  lapping  device,  the  cylinder  may  here  be 
lapped  out  by  using  the  piston  as  a  lap.  Fix  some 
form  of  *  handle  to  the  piston,  long  enough  to 
enable  the  piston  to  be  pushed  right  up  to  the  top 
end  of  the  cylinder.  With  some  fine  flour  emery 
and  oil  on  the  piston,  work  it  up  and  down  the  full 
length  of  the  cylinder,  frequently  twisting  this 
also.  Continue  this  until  the  piston  is  a  very  easy 
fit  in  the  cylinder — so  easy  that  there  is  just  the 


MAKING  A  3|-H.P.  PETEOL  MOTOR. 


57 


slightest  perceptible  shake  when  the  emery  and  oil 
are  cleaned  off.  At  the  finish,  all  trace  of  emery 
must  be  thoroughly  removed.  Finish  by  washing 
out  with  paraffin,  as  there  must  not  be  the  slight- 
est trace  of  emery  left  on  the  cylinder  or  piston. 

Piston  Eint/s. — The  turning  and  fitting  of  the 
piston  rings  will  now  be  considered.  There  are 
various  ways  of  making  piston  rings,  but  the 
method  to  be  described  here  is  as  good  as  any, 
though  entailing  more  work  than  some.  The 
time  occupied  in  turning  and  fitting  the  piston 


Fig.  39,— Section  of  Piston  on  Line  X  X  (Fig.  38). 


rings  is  time  well  spent ;  for  much  of  the  power  of 
the  engine  is  ensured  by  thoroughly  well-fitting 
rings.  Chuck  the  casting  from  which  the  rings 
are  to  be  made  by  the  projection  on  the  closed 
end.  Turn  up  the  outside  3^-}  in.,  and  bore  out 
the  inside  3Ty  in.,  keeping  outside  and  inside 
parallel  with  each  other.  Part  off,  with  a  good 
sharp  parting  tool,  four  rings  ^\  in.  wide.  They 
should  be  a  rather  tight  fit  for  the  grooves  at 
this  stage.  The  rings  should  not  be  cut  in  one 
of  the  two  ways  shown  in  Figs.  40  and  41.  That 
shown  in  Fig.  40  is  the  method  which  the  writer 


58 


MOTOR    BICYCLE    BUILDING. 


greatly  prefers,  as,  if  well  fitted,  the  joint  is  gas- 
tight  even  after  the  usual  wear  causes  the  ring  to 
part  slightly  at  the  joint;  and  if  by  accident  all 
three  ring  joints  get  in  line  when  working,  the 
gas  has  not  a  free  escape,  as  it  would  have  with 
rings  having  the  plain  diagonal  slit.  The  style 
shown  in  Fig.  41,  however,  is  the  one  generally 
adopted,  and  is  merely  a  j-in.  diagonal  cut.  To 
make  the  joint  shown  in  Fig.  40,  i  in.  is  cut 
out  each  side  for  half  the  width  of  the  ring,  the 
final  fitting  of  the  joint  being  done  with  a  very 


Fig.  40.     Fig.  41.  Fig.  42. 

Figs.  40  and  41.— Two  Methods  of  Jointing  Piston  Rings. 
Fig.  42. — Piston  Ring,  showing  Eccentricity  of    Bore. 

fine  sharp-cornered  file.  When  the  joint  is 
finished,  two  parts  should  fit  the  piston  groove 
as  tight  as  possible  when  pressed  together  to 
allow  the  parts  to  spring  away  when  released. 

The  rings,  after  the  joints  have  been  made,  are 
sprung  together  in  a  band  clip  and  fastened  to 
the  face  plate  or  a  special  chuck  made  for  the 
purpose;  the  clip  is  then  removed,  and  the  rings 
turned  and  smoothed  to  the  finished  size — 82  mm. 
They  should  just  enter  the  cylinder  freely,  but 
without  any  shake,  with  joints  tight  up.  Refer- 
ence to  Fig.  42  will  show  that  the  inner  part  of  the 


MAKING    A    Hi-H.P.    PETROL    MOTOR. 


59 


ring  is  eccentric  with  the  outside ;  this  may  be 
obtained  by  setting  the  rings  a  bare  j\s  in.  out  of 
truth  when  setting  for  the  final  turning,  or  when 
roughing  out  the  rings  the  bore  may  be  left  so 
much  smaller  to  allow  of  their  being  re-chucked 
after  the  outside  is  finished,  and  bored  out  eccen- 
tric. The  thin  part  of  the  ring  must  come  at  the 
joint.  Care  must  be  taken  not  to  get  the  thick 
portion  too  thick,  or  it  will  not  drop  below 
the  surface  of  the  piston — which  it  should  just  do. 
The  thick  part  should  be  a  bare  §  in.,  and  the 
piston  grooves  a  full  |  in.  deep,  to  make  sure  of 
this  being  correct.  In  fitting  the  rings,  a  file 
should  not  be  used  on  the  sides  if  it  can  possibly 


Fig.  43.— Exhaust  Valve  Guide. 

be  avoided.  If  the  parting  tool  is  made  with 
the  right-hand  corner  rather  more  prominent  than 
the  left  corner,  and  the  tool  is  kept  very  sharp, 
there  will  be  no  occasion  to  use  the  file  on  the 
sides.  The  rings  must  fit  the  grooves  as  tight  as 
possible,  without  binding  at  any  part.  If  the 
rings  want  easing  on  the  sides,  get  a  new  sheet 
of  fine  emery-cloth  and  tack  it  to  a  perfectly  level 
board,  and  rub  the  sides  of  the  ring  on  this  until 
a  perfect  fit  is  obtained  ;  use  only  gentle  pressure 
and  keep  the  ring  perfectly  flat. 

Exhaust     Valve     Guide. — The     exhaust     valve 
guide,  a  section  of  which  is  shown  at  Fig.  43,  is 


60  MOTOR    BICYCLE    BUILDING. 

made  from  a  piece  of  mild  steel  or  from  a  phos- 
phor-bronze casting.  The  length  over  all  is  2^  in. ; 
diameter  at  shoulder,  1  in. ;  thickness  of  shoulder, 
T\  in.  ;  bore,  y^  in.  Above  the  shoulder  it  is 
turned  to  f  in.  in  diameter  for  a  distance  of  f  in. 
up,  and  screwed  |-in.  whitworth  thread.  Below 
the  shoulder,  for  ^\  in.  down,  it  is  turned  parallel 
|  in.  in  diameter,  or  to  fit  the  inside  of  the  ex- 
haust valve  spring.  The  guide  requires  very  care- 
ful making.  The  -f^-in.  bore  must  be  quite 
straight,  and  the  threaded  part  and  the  top  of 
the  shoulder  quite  true  with  the  bore,  or  the 
exhaust  valve  will  not  shut  true  on  its  seating. 
The  TV*n-  h°le  should  be  bored  with  a  twist  drill 
or  reamered  out  with  a  -f^-in.  parallel  rimer. 


Fig.  44.  Fig.  45. 

Fijrs.  44  and  45.— Exhaust  Valve. 

Three  or  four  |-in.  tommy  holes  should  be  drilled 
in  the  face  of  the  shoulder  for  tightening-up  pur- 
poses. For  turning  with  a  spanner,  this  part  may 
be  made  hexagon,  or  two  flats  may  be  filed  on  it. 
The  last  thread  next  to  the  shoulder  should  be 
undercut,  to  ensure  the  shoulder  bedding  down 
true  on  the  under  side  of  the  valve  chamber, 
which  has  been  trued  to  receive  it.  This  fitting 
will  not  require  hardening. 

Exhaust  Valve. — The  exhaust  valve  (Figs.  44 
and  45)  should  be  made  from  a  single  forging — 
that  is,  the  forging  should  be  made  from  one 
piece  of  mild  steel,  and  should  not  have  the  head 
welded  on  to  the  spindle.  If  thought  desirable, 
•however,  it  may  be  made  by  screwing  the  end  of 


MAKING  A  34-H.P.  PETROL  MOTOR. 


61 


the  stem,  tapping  the  head  to  suit,  and  riveting 
the  end  over  into  a  light  countersink  in  the  head. 
If  made  in  this  way,  it  would  be  an  advantage 
to  have  the  head  of  close-grain  cast-iron.  The 
stem  A  should  be  turned  up  T5ff  in.  a  nice  free  fit, 
without  shake,  in  the  valve  guide.  Finish  off 
with  the  dead  smooth ;  and  for  f  in.  to  f  in.  from 
the  under  side  of  the  head  leave  the  part  B  full 
|  in.,  as  this  portion  of  the  stem  is  liable  to  get 
weakened  by  the  exhaust  gases.  The  head  is 
barely  1^  in.  in  diameter,  and  should  pass  freely 
through  the  inlet  valve  seating  in  the  top  of  the 
valve  chamber.  Chamfer  the  edges  to  suit  the 


Figs.  46  and  47.— Inlet  Valve  Body. 


angle  turned  on  the  exhaust  valve  seating.  A 
projection  for  grinding-in  purposes  is  left  on  the 
head  of  the  valve  as  shown,  and  a  saw-cut  made 
across  it  as  indicated  also  in  Fig.  45.  The  cham- 
fer on  the  valve  head  must  be  true  with  the  stem, 
and  for  this  reason  it  ie.  advisable  to  turn  the 
whole  of  the  valve  in  one  position  on  the  lathe 
centres,  as  it  is  seldom,  that  a  perfectly  true  piece 
can  be  produced  by  turning  one  portion  in  one 
position  and  another  with  the  piece  reversed  on 
the  centres.  This  proves  the  advantage  of  making 
the  valve  from  a  forging,  as  an  extension  can  be 
left  on  above  the  head  long  enough  for  the  carrier 


62  MOTOR    BICYCLE    BUILDING. 

to  drive  by,  this  being  cut  off  after  the  turning 
is  finished.  The  length  from  the  under  seating  to 
the  end  of  the  stem  is  6  in.,  and  the  thickness  of 
the  head  at  the  seating  is  a  bare  |  in.,  tapering 
to  the  centre,  and  finished  off  with  a  good  round 
shoulder.  The  valve  is  now  finished,  excepting 
the  cotter  slot  or  hole  near  the  end  of  the  stem. 
The  exact  position  of  this  should  not  be  determined 
until  fitting  up,  as  if  the  exhaust  valve  spring 
is  purchased  ready-made  the  position  will  depend 
on  the  length  and  strength  of  the  spring.  A  slot 
^  in.  by  ,,5f  in.  is  best;  but  as  this  is  a  trouble- 
some job,  a  hole  may  be  drilled  a  bare  |  in.  and 
a  round  cotter  used.  The  cotter,  either  flat  or 
round,  should  be  f  in.  long,  to  fit  the  recess  in  the 
under  part  of  the  washer,  to  be  described  later. 
Inlet  Valve. — The  body  of  the  inlet  valve  is 
shown  at  Figs.  46  and  47.  It  is  an  iron  casting, 
and  is  turned  all  over,  excepting  inside  between 
the  three  arms.  The  casting  should  be  chucked 
by  the  top  projection,  and  drilled  i  in.,  and  then 
turned  up  to  within  -^  in.  of  the  finished  size, 
the  final  turning  being  done  on  a  true  mandrel 
between  the  centres.  The  mandrel  being  so  small 
in  diameter,  only  the  lightest  cut  is  possible  to 
avoid  springing  and  consequent  want  of  truth 
in  the  finished  valve  body.  The  diameter  in  the 
largest  part  is  1  ^'  in.  ;  diameter  under  the  cham- 
fered portion,  \\  in.  ;  stem  c,  -^  in.  long  by  J  in. 
in  diameter ;  depth  without  stem,  f  in.  If  the 
inner  portion  between  the  arms  requires  filing 
out,  this  should  be  done  before  it  is  turned.  The 
other  part  of  the  valve  (Fig.  48)  is  made  in  the 
same  way  as  the  exhaust  valve,  but  it  is  much 
lighter  and  the  head  is  of  a  different  pattern. 
The  front  view  is  similar  to  Fig.  45,  but  the 
diameter  is  only  1T7^  in.  The  stem  is  J  in.  in 
diameter  by  1|  in.  long  under  the  head.  The 
head  is  ly7^  in.  by  a  bare  3  in.  thick,  the  under 
side  being  recessed  -^  in.  deep  to  within  T^  in.  of 


MAKING    A    3i-H.P.    PETROL    MOTOR.  63 

the  edge.  The  end  of  the  stem  is  screwed  twenty- 
four  threads  to  the  inch  for  f  in.  of  its  length. 
It  should  be  a  very  easy  fit  in  the  ^-in.  hole  of 
the  body,  with  just  the  least  perceptible  shake. 

Grinding  Valves. — Both  valves  may  now  be 
ground  into  their  seatings  with  a  little  of  the 
finest  flour  emery  and  oil.  In  grinding  in  the 
exhaust  valve,  the  guide  (Fig.  43)  must  be  firmly 
screwed  up  into  its  place  in  the  cylinder.  The 
body  of  the  inlet  valve  must  be  ground  into  its 
seating  in  the  cylinder  in  the  same  way,  to  make 
a  gas-tight  fit.  Remove  all  trace  of  emery  when 
finished. 

Screwed  Washer  and  Nut  for  Inlet  Valve. — 
A  screwed  washer  and  nut  (Figs.  49  and  50)  will 
be  required  to  complete  this  valve.  The  washer 


^ 

!•— -^—  ---•--- 


Figs.  48  to  50.— Head  and  Stem.  Washer,  and  Lock-nut  of 
Inlet  Valve.     Fig.  51.— Spring  Washer  of  Exhaust  Valve. 

is  |  in.  in  diameter  at  the  shoulder  and  i  in. 
under  by  j  in.  deep,  and  is  tapped  for  J  in., 
twenty-four  threads  to  the  inch,  to  suit  the 
screwed  portion  of  the  stem;  the  lower  part  fits 
inside  the  spring,  keeping  it  central.  The  lock- 
nut  is  an  ordinary  hexagon  i  in.  by  twenty-four 
threads  nut,  with  a  saw-cut  half-way  through. 
If  this  nut  is  tightened  up  on  to  the  lower  washer, 
with  the  spanner  gripping  the  upper  half  above 
the  saw-cut,  it  will  not  get  loose.  Two  flats 
should  be  filed  on  the  shoulder  of  the  screwed 
washer  to  hold  it  whilst  locking  the  nut. 

Washer  for  Exhaust  Valve  Spring. — A  washer 
should  be  prepared  as  in  Fig.  51  for  the  exhaust 


64  MOTOR    BICYCLE    BUILDING. 

spring.  This  washer  is  I  in.  in  diameter  by 
\  in.  deep,  with  a  ^6-  -in.  plain  hole  to  fit  the 
stem  of  the  exhaust  valve ;  it  is  turned  down 
on  the  top  to  fit  the  inside  of  the  exhaust  spring, 
and  the  under  side  is  recessed  £  in.  in  diameter 
to  take  the  cotter  passed  through  the  stem.  This 
washer  serves  the  double  purpose  of  holding  up 
the  exhaust  spring  quite  central  and  keeping 
the  cotter  from  coming  out  of  the  stem. 

Valve  Springs. — In  making  the  valve  springs, 
a  certain  amount  of  experiment  with  various 
strengths  of  inlet  valve  springs  is  necessary  to  get 
the  best  results  from  the  engine.  If  too  weak  a 
spring  is  used,  the  engine  may  start  very  easily, 
but  it  wrill  never  develop  its  full  power  nor  at- 
tain a  high  speed ;  while  if  too  strong,  it  will  be 
difficult  to  start  unless  a  fair  amount  of  speed 
is  got  up  before  dropping  the  exhaust  lift,  and 
the  engine  will  run  badly  at  slow  speeds.  The 
method  of  holding  the  spring  in  position  with 
the  adjustable  nut  and  washer,  as  above  described, 
will  allow  of  a  certain  amount  of  adjustment  of 
tension.  A  spring  that  should  suit  this  is  one 
made  from  No.  17  or  No.  18  gauge  wire,  1^  in. 
long,  with  about  twelve  turns,  and  i  in.,  in 
diameter  inside. 

Valve  Stems  Breaking. — Trouble  is  sometimes 
experienced  with  this  class  of  valve  through  the 
ends  of  the  stems  breaking  off  just  at  the  end  of 
the  threaded  portion,  caused  by  the  jar  of  the 
nut  and  washer  on  the  top  of  the  body  at  high 
speeds.  This  may  be  remedied  by  fitting  a  small 
spring  inside  the  other  one,  making  it  a  free  fit 
on  tne  valve  spindle.  It  may  be  made  from  No.  15 
gauge  wire  with  about  two  turns,  and  of  such  a 
length  as  to  come  into  operation  only  when  the 
valve  has  opened  a  full  -|  in.  The  exhaust  valve 
spring  being  mechanically  operated,  the  same  de- 
gree of  nicety  of  strength  is  not  necessary,  but  it 
must  be  strong  enough  to  shut  the  valve  sharply 


MAKING    A    Si-H.P.    PETROL    MOTOR. 


and  firmly  when  released,  otherwise  there  will  be 
loss  of  compression.  If  the  spring  is  too  strong, 
there  will  be  excessive  wear  and  tear  of  the  tap- 
pet rod  and  cam,  and  this  may  cause  a  fracture 
of  the  valve  just  under  the  head.  A  suitable 
spring  can  be  made  from  No.  14  or  No.  15  gauge 
wire,  2i  in.  long  and  £  in.  in  inside  diameter, 
with  about  twenty  turns. 

Machining  Crank  Case. — Now  proceed  with  the 
machining  of  the  crank  case  (see  Figs.  52  to  54). 
Trim  up  the  crank-case  castings,  and  set  true,  if 
necessary,  as  it  frequently  happens  that  large, 
light  castings  of  this  kind  got  warped  or  bent  at 


Fijr.  52.— Plan  of  Cylinder  End  of  Crank  Case. 

the  foundry  or  in  transit.  Chuck  one  of  the  cast- 
ings by  the  central  boss  and  turn  the  edge  true, 
and  form  half  the  joint,  as  shown  in  section  at 
Fig.  54.  The  taper  of  this  joint  is  exaggerated  for 
clearness ;  it  should  have  only  about  1°  of  taper. 
Face  up  the  boss,  where  the  shoulder  of  the  bush 
bads,  and  bore  out  the  hole  for  the  bush  lj  in. 
The  depth  of  the  half  case  from  the  edge  of  the 
joint  to  the  inner  face  of  the  casting  should  be  If 
in.  The  face  of  the  boss  is  about  J  in.  deep.  The 
exact  depth  of  these  bosses  on  the  inside  of  the 
crank  case  should  be  determined  after  the  fly- 
wheels are  finished  and  fitted  on  their  spindles,  so 
that  the  distance-  between  the  two  bushes,  when 


66  MOTOR    BICYCLE    BUILDING. 

the  halves  of  the  crank  case  are  fitted  together, 
is  -L-  in.  wider  than  the  distance  from  face  to  face 
of  the  outer  bosses  of  the  flywheels.  If  it  is  found 
necessary  to  reduce  these  crank-case  bosses,  the 
casting  should  be  tapped  on  to  a  true  mandrel,  run 
between  the  lathe  centres  for  the  purpose. 

The  other  half  of  the  crank  case  should  be 
machined  in  the  same  way  as  the  first,  special  care 
being  taken  to  get  the  joint  a  good  oil-tight  fit. 
To  insure  this,  turn  the  joint  until  it  comes  to 
within  a  bare  ^V  in-  °f  closing  ;  then  put  a  little 
powdered  pumice  and  oil  on  the  joint  faces  and 
grind  it  in  to  fit ;  this  should  be  done  while  the 
second  half  is  in  the  chuck,  as  the  grinding-in  of 
the  joint  can  be  finished  by  running  the  lathe  with 
the  two  halves  pressed  lightly  together.  Clean  off 
the  pumice  and  oil,  and  run  again  for  a  few 
minutes  with  oil  only.  This  done,  mark  the  posi- 
tion for  the  half-time  shaft  bush  A  (Fig.  54),  and 
drill  the  hole  y|  in.  in  diameter  in  the  one  half  of 
the  case.  This  must  be  done  very  carefully,  with 
the  centre  exactly  l^in.,  from  the  centre  of  the 
main  shaft  bearing.  Unless  this  is  exact,  the 
teeth  of  the  gear  wheels  will  not  mesh  correctly. 
In  drilling  the  hole,  which  must  be  perfectly  paral- 
lel with  the  main  shaft  bore,  a  small  drill,  about 
J  in.,  should  first  be  run  through.  If  the  casting 
is  placed  face  downwards  on  an  upright  drilling 
machine  table,  there  should  be  no  difficulty,  pro- 
vided the  spindle  is  true  with  the  table.  At  this 
time  the  face  of  the  boss  should  be  trued  up  with  a 
facing  cutter  until  the  hole  is  \  in.  deep.  With 
this  half  of  the  case  on  a  mandrel,  turn  off  the 
face  of  the  gear  case  until  it  is  if  in.  deep.  The 
outside  of  the  main  shaft  boss  is  also  turned  up 
true  to  l-i£  in.  in  diameter. 

The  two  halves  of  the  crank  case  are  now  put 
together,  a  bolt  is  passed  through  the  centre  holes, 
and  screwed  up  with  a  nut  and  washer. 

Cylinder  End  of  Crank  Case. — The  case  is  now 


MAKING    A    3i-H.P.    PETROL    MOTOR 


^\o'r^ 


68  MOTOR    BICYCLE    BUILDING. 

fastened  true  to  the  face  plate,  and  the  top  flange 
to  take  the  cylinder  (see  upper  part  of  Fig.  53, 
which  is  a  plan  of  the  gear  side  of  the  crank  case) 
turned  true  ;  this  fa/os  is  4^  in.  from  the  centre  of 
the  case.  The  recess  B  for  the  cylinder  end  is 
turned  out  y\  in.  deep  by  3^  in.  in  diameter,  and 
should  be  a  good  tight  push  fit.  The  surface  round 
the  connecting-rod  slot  should  be  faced  up  true  and 
left  3^  in.  in  diameter.  In  setting  the  crank  case 
on  the  face  plate  for  this  operation,  it  must  be 
made  absolutely  true  with  the  central  hole,  or  the 
connecting-rod  bearings  will  bind. 

Bolt  Holes  in  Crank  Case. — The  six  f-in.  holes 
shown  in  Fig.  52  take  the  bolts  which  hold  the 
halves  of  the  case  together,  and  may  now  be 
marked  off  and  drilled.  After  drilling  the  first 
hole,  a  f-in.  bolt  may  be  put  through  and  tightened 
up  to  prevent  the  halves  shifting  during  the  drill- 
ing of  the  remaining  five  holes.  These  holes 
should  be  drilled  in  the  lathe,  halfway  from  each 
side,  using  a  f-in.  twist  drill  for  the  purpose,  and 
afterwards  clearing  out  with  a  parallel  rimer. 

Crank  Case  Bolts. — Four  of  the  bolts  which 
hold  the  halves  together  may  be  plain  f-in.  bright 
drawn  steel,  screwed  for  f  in.  at  each  end  to  re- 
ceive suitable  nuts  (the  standard  back-wheel  cycle- 
nuts  may  be  used)  ;  these  are  screwed  for  f  in. — 
26  threads  to  the  inch.  On  account  of  the  nuts 
being  in  the  way  of  the  belt,  two  of  the  pins  will 
have  to  be  made  with  countersunk  heads,  and  the 
crank  case  countersunk  to  suit  them ;  these  two 
holes  will  be  the  rear  top  and  bottom  ones  on  the 
left-hand  or  pulley  side  of  the  engine.  Small  pegs 
should  be  inserted  under  the  heads  of  these  two 
pins,  and  suitable  slots  cut  in  the  case  counter- 
sink, to  prevent  them  turning  in  the  holes  when 
the  nuts  are  tightened  or  slackened. 

The  five  holes  c  (Fig.  52)  in  the  gear  case, 
tapped  |  in.  whitworth,  should  be  left  until  after 
the  gear-case  cover  is  drilled. 


MAKING    A    3i-H.P.    PETROL    MOTOR.  69 

Hole  for  Oil-pipe  Connection.— A  hole  to  re- 
ceive the  oil-pipe  connection  from  the  pump  will 
be  necessary ;  this  should  come  about  halfway 
between  the  two  |-in.  bolt  holes  on  the  front 
of  the  case  in  the  upper  half.  The  drilling  and 
tapping  should  be  left  until  this  fitting  is  in  hand, 
as  the-  size  and  screwing  vary. 

Waste-oil  Outlet. — A  waste-oil  outlet  should  be 
drilled  and  tapped  J-in.  whitworth  in  the  extreme 
bottom  of  the  case;,  and  a  screw  inserted. 

Air-release  Valve. — An  air-release  valve  will  be 
fitted,  and  should  be  placed  as  near  the  centre  of 
the  gear  side  as  possible.  As  the  valve  can  be 
purchased  for  a  few  pence,  it  is  not  worth  while 
to  make  it ;  a  suitable  size  will  be  one  screwed  for 
|  in.,  26  threads  to  the  inch. 

Oil  Holes  in  Crank  Case. — Oil  holes  will  be 
required,  one  above  each  of  the  man-shaft  bear- 
ings and  one  just  above  the  half-time  shaft  bear- 
ing (see  Fig.  54).  They  should  all  have  shallow 
V-  shaped  grooves  cut  in  the  side  of  the  case  lead- 
ing to  these  oil  holes;  the  V-grooves  catch  the  oil 
running  down  the  case  sides  and  lead  it  to  the 
holes.  The  one  above  the  half-time  shaft  bearing 
is  drilled  right  through,  and  is  intended  fo,r  oiling 
tne  gear  wheels  and  half-time  shaft.  The  two 
leading  to  the  main-shaft  bearings  are  drilled  after 
the  phosphor-bronze  bushes  have  been  fitted. 

Attaching  Cylinder  to  Crank  Case. — The  cylin- 
der may  now  be  fitted  to  the  "top  of  the  crank  case, 
and  the  four  holes  for  holding  the  two  parts  to- 
gether (see  Fig.  53)  marked  off,  drilled,  and 
tapped.  They  are  given  f  in.  clearance  in  the 
cylinder  flange,  and  tapped  f-in.  whitworth  in  the 
crank  case.  Four  studs  to  suit  should  be  made  for 
screwing  permanently  into  the  top  of  the  crank 
case.  Ordinary  f-in.  set  pins  may  be  used  for  this 
purpose,  but  studs  and  nuts  make  a  more  lasting 
job,  as  the  thread  in  the  soft  aluminium  is  liable  to 
strip.  When  the  four  studs  or  pins  are  fitted  and 


70  MOTOR    BICYCLE    BUILDING. 

screwed  up,  the  four  sides  of  the  flanges  may  be 
filed  flush.  In  finally  fitting  the  cylinder  to  the 
crank  case,  a  stout  brown-paper  washer  may  bo 
inserted  between  the  two  surfaces.  It  should  be 
noted  that  the  recess  in  the  top  of  the  crank  case 
is  slightly  deeper  than  the  length  of  the  projection 
on  the  bottom  of  the  cylinder. 

Gear-case  Cover. — The  gear-case  cover,  shown 
in  section  at  Fig.  55,  will  require  turning  to  two 
different  settings  inside.  First  chuck  the  casting 
with  the  half-time  shaft  bearing  as  centre,  and 
turn  out  2  ^  in.  by  |  in.  deep,  facing  off  the  edge 
as  far  as  the  top  lug  will  allow  ;  then  shift  the  cast- 
ing \\^  in.  out  of  the  centre,  and  turn  out  the  lower 
part  l|  in.  in  diameter  to  the  same  depth,  and  face 
the  edge  to  meet  the  first  facing.  This  job  re- 
quires very  careful  setting  in  the  chuck  to  get  the 
facing  of  the  edge  true  ;  and  unless  this  is  so,  and 
a  good  Level -fit  on  the  gear-case  half,  an  oil-tight 
fit  cannot  be  obtained.  The  five  ^-in.  holes  should 
then  be  marked  off,  drilled,  and  countersunk.  The 
five  holes  in  the  crank-case  half  of  the  gear  case 
can  now  be  drilled  and  tapped,  the  cover  being 
used  as  a  template  for  marking  them  off.  The 
i-in.  hole  in  the  cover  to  receive  the  other  bronze 
bush  for  the  half-time  shaft  should  be  drilled  with 
a  J-in.  twist  drill,  after  the  bush  has  been  fitted  in 
the  crank  case  ;  this  bush  having  a  J-in.  hole,  the 
drill  can  be  passed  through  that  as  a  guide,  to 
insure  the  hole  in  the  cover  being  perfectly  true 
with  it. 

While  the  cover  is  fixed  to  tne  case,  the  hole. in 
the  top  lug  for  the  tappet-rod  guide  should  be 
marked  off,  drilled,  and  tapped  f-in.  whitworth. 
The  top  of  the  lug  should  then  be  faced  off,  so 
that  the  screwed  part  is  -|-i  in.  deep.  The  outside 
of  the  cover  will  require  turning,  also  the  pro- 
jection to  receive  the  contact-breaker  bearing,  the 
exact  size  of  which  should  be  left  till  the  contact- 
breaker  is  purchased. 


MAKING  A  3|-H.P.  PETROL  MOTOR. 


71 


Bearing  Bushes. — The  bearing  bushes  for  this 
motor  will  be  hard  phosphor-bronze  castings,  as 
this  metal  will  give  the  best  all-round  results. 
Several  good  makers  use  hardened  steel  bearing 
bushes  on  their  .engines,  and  these,  if  thoroughly 
well  fitted  and  lubricated,  give  good  results  ;  but 
to  make  a  success  of  bearings  so  fitted,  the  shafts 
and  bushes  require  careful  hardening  and  grinding, 
and  lapping  true  after  hardening,  involving  the 
use  of  special  tools.  One  point  against  steel  bushes 


Fig.  55.— Section  of  Gear  Cover. 


is  the  liability  of  the  shafts  to  seize  or  jam  if 
lubrication  fails  at  any  time.  The  phosphor- 
bronze  bushes  will  generally  outlast  the  steel 
shafts  if  the  metal  and  workmanship  is  good,  and 
they  have  the  advantage  of  being  easier  to  fit. 
They  are,  however,  somewhat  troublesome-  to 
machine,  as  the  tool  soon  loses  its  edge  on  the  first 
cut,  or  if  the  lathe  is  run  at  too  fast  a  speed.  A 
slow  speed  will  be  found  best^  about  the  same  as 
for  cast-iron,  or  even  slower,  especially  for  the  first 


72  MOTOR    BICYCLE    BUILDING. 

cut,  until  the  outer  skin  is  removed.  It  will  save 
time  in  tool-grinding  if  the  castings  are  rough-filed 
all  over,  inside  and  outside,  before  starting  to  bore 
or  turn. 

Main-shaft  Bushes. — The  main-shaft  bushes, 
which  are  shown  in  place  in  the  crank  case  at  Fig. 
54  (p.  67),  are  bored  and  turned  to  the  following 
dimensions  :  The  long  or  pulley  side  bush  is  bored 
i  in.,  and  turned  up  on  a  perfectly  true  mandrel 
lj  in.  in  diameter  by  2^  in.  long  over  all,  the 
shoulder  being  U  in.  in  diameter.  The  bore  must 
be  absolutely  parallel,  and  as  smooth  as  possible. 
If  a  f-in.  reamer  is  not  available,  the  bore  should 
be  finished  out  with  a  good  sharp  boring  tool  hav- 
ing a  flat  cutting  edge.  But  the  best  way  is  to 
finish  the  bore  just  a  shade  under  f  in.,  and  pass  a 
f-in.  reamer  through  the  two  bushes  after  they  are 
in  place  and  the  two  halves  of  the  crank  case 
bolted  together ;  this  will  insure  the  two  bearings 
being  perfectly  in  line.  The  short  bush  for  the 
gear  side  of  the  crank  case  is  the  same  in  bore  and 
outside  diameter  as  the  long  one,  but  is  only  lA  in. 
long.  These  bushes  must  be  a  good  tight  fit  in 
their  places,  and  to  insure  this  they  should  be 
shrunk  in  hot.  They  should  be  turned  to  fit  tight 
about  halfway  in — that  is,  the  bushes  should  only 
enter  their  bosses  in  the  crank  case  about  halfway 
when  cold.  The  crank  case  is  then  heated  to  about 
the  heat  of  a  good  hot  soldering-iron,  and  the  bush 
pressed  or  knocked  in  with  a  mallet  and  cooled  off 
at  once.  A  small  grub  screw  should  be  fitted  half 
in  the  bush  A  (Fig.  54)  and  half  in  the  crank  case, 
to  prevent  the  bush  turning  in  the  boss.  The  ends 
of  the  bushes  and  boss  can  now  be  faced  off  level 
on  a  mandrel  in  the  lathe. 

Bush  for  Half-time  Shaft.— The  bush  for  the 
large  end  of  the  half-time  shaft  is  bored  J  in.  and 
turned  Ti  in.  by  *f  in.  long,  the  shoulder  being 
1-^0  in.  in  diameter.  This  should  be  shrunk  in,  in 
tbip  same  way  as  the  main  bushes,  and  secured 


MAKING    A    3|-H.P.    PETROL    MOTOR.          73 

with   two    small   grub   screws   fitted   through   the 
shoulder. 

Bush  in  Gear  Cover.—  The  bush  in  the  gear 
cover  is  bored  f  in.,  and  is  A  in.  in  diameter  by 
•fi-in.  long,  with  the  shoulder  i£  in.  in  diameter. 
It  will  be  noticed  that  the  shoulder  of  this  bush  is 
let  in  flush  with  the  cover  (see  Fig.  55,  p.  71). 
It  is  secured  with  a  small  grub  screw.  A  small  oil 
channel  should  be  chipped  or  filed  from  the  oil 
hole  just  above-  the  half-time  shaft  in  the  crank 
case,  to  the  edge  of  the  bush,  so  that  the  oil  may 
run  down  to  the  shaft  and  exhaust  cam. 


Fig:.  59. 


Figs.  58  and  59.— Valve-lift 
Lever. 


Figs.  56  and  57. — Tappet 
Guide. 


Tappet-rod  Bush. — The  tappet-rod  bush  (Figs. 
56  and  57)  is  a  phosphor-bronze  casting,  and  is 
bored  at  A  /^in.  in  diameter  and  turned,  the  bot- 
tom part,  which  is-^i  in.  long,  being  screwed  f  in. 
whitworth  to  fit  tight  in  the  tapped  hole  in  the 
top  of  the  gear  cover ;  the  shoulder  at  the  top  is 
turned  to  the  same  diameter  as  that  of  the  lug 
thereon.  When  this  bush  is  screwed  right  home, 
the  small  boss  (see  Fig.  57)  and  the  hole  B  (Fig.  56) 
must  come  to  the  front ;  if  this  does  not  do  so  at 
the  first  trial,  a  little  should  be  faced  off  the  under 
side  of  the  shoulder  until  it  does.  The  hole  B  on 


74  MOTOR    BICYCLE    BUILDING. 

the  front  of  the  bush  is  drilled  and  tapped  J-in. 
whitworth,  and  the-  boss  is  |  in.  in  diameter  by  -^ 
in.  deep.  This  is  to  take  the  exhaust  valve  lifter 
(Figs.  58  and  59),  which  is  also  a  phosphor-bronze 
casting.  It  is  drilled  at  c  i-in.  clearance,  and  re- 
cessed out  to  fit  the  small  boss  on  the  tappet^rod 
guide,  being  secured  thereto  with  a  J-in.  screw. 

Exhaust-Valve  Lift.— The  working  of  this  ex- 
haust-valve lift  is  as  follows :  The  circular  steel 
plate  riveted  to  the  tappet  rod  is  raised  by  the 
upper  side  of  the  valve-lift  lever,  and  with  it  the 
tappet-rod  and  exhaust-valve  stem,  when  the  lever 
is  lifted  by  the  projection  on  the  other  end.  This 
projection  engages  with  a  plate  fixed  to  the  lower 
end  of  the  rod  which  actuates  the  contact-breaker, 
and  comes  into  operation  when  the  spark  is  re- 
tarded to  its  uttermost.  By  this  arrangement  one 
lever  does  duty  for  the  two  purposes— spark  ad- 
vance and  valve  lift.  This  valve-lift  lever  is  filed 
and  smoothed  all  over. 

Connecting-rod  Bushes. — The  only  other  bronze 
bushes  to  be  made  are  the  two  fitted  to  the  con- 
necting-rod (Figs.  60  and  61),  which  is  a  mild  steel 
forging,  machined  all  over.  The  forging  should  be 
made  by  an  experienced  smith,  and  should  be 
forged  from  the  solid.  A  drop  forging  made  under 
a  steam  stamp  is  just  as  good,  if  it  can  be  ob- 
tained. A  casting  is  sometimes  used  for  this  job, 
either  of  malleable  iron  with  bronze  bushes  or  a 
solid  bronze  casting.  It  is  not  advisable,  however, 
to  use  a  casting  in  such  a  case  for  this  size  of 
engine.  The  dimensions  are  :  Length  from  centre 
to  centre,  7-j5^  in.  ;  large  boss  D,  l\  in.  long  by  li 
in.  in  diameter  at  the  edges  ;  small  boss  E,  l|  in. 
long  by  1  in.  in  diameter  at  the  edges;  width  and 
thickness  at  the  large  boss  end,  1  in.  by  f  in.  ; 
width  and  thickness  at  the  small  end,  f  in.  by 
T\  in.  The  bosses  should  be  centred  and  drilled 
7T5g-  in.  apart,  with  the  holes  parallel  with  each 
other,  the  large  end  1  in.  and  the  small  end  f  in. 


MAKING  A  3|-H.P.  PETKOL  MOTOR. 


The  bosses  can  be  turned  and  faced  on  a  mandrel 
in  the  lathe.  The  main  portion  may  be  milled, 
shaped,  turned,  or  filed,  according  to  what  tools 
are  available.  The  bushes,  which  are  shown  in 
position  in  Figs.  60  and  61,  are-  If  in.  long  by  1  in. 
outside  diameter,  by  f  in.  bore  at  the  large  end, 
and  2g  in.  long  by  1  in.  diameter  by  ^  in.  bore  at 
the  small  end.  The  same  instructions  as  regard^ 
fitting  apply  as  in  fitting  the  crank-case  bushes, 
only  that  it  is  still  more  important  that  they 


Figs.  60  and  61. — Connecting  rod. 

should  be  a  good  tight  fit,  or  they  will  become 
loose.  Two  J-in.  screws  should  be  put  through  the 
boss  and  bush  to  keep  the  bushes  from  turning. 
The  screws  should  be  run  in  till  the  ends  are  level 
with  the  bore  ;  the  head  part  should  then  be  cut 
off  level  with  the  outside,,  and  the  edge  of  the 
hole  burred  over  to  prevent  the  screw  from  coming 
out.  An  oil  hole  should  be  drilled  in  the  centre  of 
the  small  end  and  countersunk,  two  oil  holes  being 
drilled  in  the  large  end,  one  on  each  side,  meeting 


MOTOR    BICYCLE    BUILDING. 


on  the  inside  of  the  bush.  An  oil  groove  should  be 
filed  along  the  inner  surface  of  the  bush  to  dis- 
tribute the  oil. 

It  is  very  important  that  the  holes  in  the  two 
ends  of  the  connecting-rod  should  be  absolutely 
parallel  with  each  other  in  all  directions,  and  it 
may  therefore  be  necessary  to  set  the  rod  to  bring 
this  about.  Slip  a  mandrel  through  each  end,  and 
test  this  by  measurement ;  if  it  requires  bending  or 
twisting,  this  may  be  done  cold. 

Union  Nut  for  Induction  Pipe. — The  union 
nut  for  connecting  the  inlet  or  induction  tube  from 
the  carburetter  to  the  cylinder  is  shown  in  plan 


Fig.  62. 


Fig.  63. 


Figs.  62  and  63.— Union  Nut. 

and  section  at  Figs.  62  and  63.  It  may  be  a  phos- 
phor-bronze, gunmetal,  or  brass  casting,  machined 
all  over  to  the  following  dimensions  :  Bore,  l^Vin. ; 
diameter  at  the  screwed  part,  If  in.  by  twenty 
threads,  to  fit  easily  the  screwed  opening  in  the 
valve  chamber  of  the  cylinder  ;  length  of  screwed 
part,  J  in.  ;  diameter  of  collar,  2Tlw  in.  ;  depth,  J  in. 
Means  for  tightening  and  slackening  this  out  must 
be  provided,  either  by  filing  four  slots  in  the  edge 
of  the  collar,  as  shown,  by  drilling  tommy  holes, 
or  by  filing  the  collar  hexagon.  By  adopting  the 
first  method,  the  nut  can  always  be  undone  on  the 


MAKING    A    3|-H.P.    PETROL    MOTOR.  77 

road  by  using  a  large  nail  or  anything  else  handy 
as  a  punch,  and  a  spanner  or  stone  as  a  hammer, 
in  the  absence  of  a  suitable  large-  spanner  to  fit. 

Flywheels. — The  two  flywheels  may  now  be 
taken  in  hand.  Fig.  64  is  a  plan  of  one  of  them, 
and  Fig.  65  a  section.  They  are  7T7^  in.  in  out- 
side diameter  and  lj  in.  wide  on  the  rim,  and 
weigh  about  24  Ib.  the  pair.  If  the'  casting  is 


Fig.  64. 
Figs.  64  and  65.— Flywheel. 


Fig.  65. 


chucked  on  the  jaws  of  a  three-  or  four-jaw  chuck, 
letting  the  jaws  grip  outward  into  the  deep  recess 
under  the  rim,  nearly  the  whole  of  one  side  and 
edge  of  the  rim  may  be  machined  at  one  opera- 
tion. Turn  up  the  rim  7T7^  in.  in  diameter,  and 
true  up  the  face  of  the  rim  and  the  inner  edge. 
Face  off  the  centre  recess  If  in.  in  diameter  by 
|  in.  deep  from  the  rim  face  ;  bore  a  f-in.  hole  in 
the  centre  for  the  main  shaft,  then  set  the  slide- 


73  MOTOR    BICYCLE    BUILDING. 

rest  to  3  degrees  of  taper  and  turn  out  the  taper 
for  the  shaft  end ;  this  should  bring  the  large  end 
of  the  hole  to  f  in.  To  make  a  really  good  and 
true  job  of  these  taper  holes,  a  reamer  having  a 
suitable  taper  (3  degrees)  should  be  used  to  finish 
out  the  taper,  in  which  case  the  holes  should  be 
left  from  the  boring  tool  a  shade  under  the  sizes 
mentioned.  The  reamer  should  be  used  by  bring- 
ing up  the  back  centre  as  a  support  for  the  end  of 
the  reamer,  and  by  fixing  a  lathe  carrier  to  the 
reamer.  A  mark  should  be  made  on  the  face  of 
the  reamer  to  insure  the  tool  being  run  up  to  the 
same  depth  in  both  holes.  The  job  can  be  done 
without  this  tool,  but  care  must  be  taken  to  get 
the  rest  set  to  exactly  the  same  taper,  and  the 


Fig-.  06.— Main  Shaft,  Pulley  Side. 

tool  taken  to  the  same  depth,  each  time.  The 
other  flywheel  may  now  be  treated  in  the  same 
manner. 

The  other  side  of  the  castings  has  now  to  be 
turned,  but  this  time  the  casting  must  be  held 
by  the  outside  of  the  rim,  as  the  recess  on  this 
side,  under  the  rim,  is  not  deep  enough  for  the 
jaws  to  grip.  Turn  up  the  face  of  the  rim  to 
make  the  thickness  1|  in.  ;  and  true  the  centre 
part  so  that  it  is  ^V  in-  through  from  the  other 
face.  Serve  the  other  casting  in  the  same  way. 
The  casting  must  now  be  marked  off  for  the 
crank  pin  hole.  This  is  41  mm.,  or  roughly  If  in. 
bare.  To  machine  this  hole,  fix  a  f-in.  stud  to  the 
face  plate,  41  mm.  out  of  the  centre;  the  casting 
can  then  be  slipped  over  this  stud  by  the  centre 


MAKINTG    A    3A-H.P.    PETROL    MOTOR.  79 

hole  and  brought  round  till  the  truly  marked-off 
centre  for  the  crank  pin  is  in  the  desired  place. 
Strap  the  casting  down  firmly  to  the  face  plate, 
and  bore  a  |-in.  hole  through,  and  turn  out  to 


<>7  —  Main  Shaft,  Gear  Side. 


the  same  taper  as  the  main  shaft  holes— namely, 
3  degrees.  This  will  bring  the  large  side  £  in. ; 
face  off  round  this  opening  till  it  is  i  in.  below 
the  surface  of  the  rim  face.  The  other  side  of 
this  hole  will  require  facing  true,  for  the  nut  to 
bed  against.  For  this  operation  the  casting  must 
be  reversed  again  on  the  face  plate.  The  thick- 
ness through  at  this  part  is  4  in.  full.  The  rim 
of  the  flywheels  may  be  finally  trued  up  by  mount- 
ing them  on  their  respective  shafts,  when  these 
have  been  turned,  and  running  on  the  lathe 
centres. 

Main  Shaft,  and  Crank  Pin. — Fig.  G6  shows  the 
main  shaft,  pulley  side,  and  Fig.  67  the  gear  side. 


3  Me * 

Fig.  68.— Crank  Pin. 

Fig.  68  is  the  crank  pin.  These  may  be  turned 
from  good  mild  steel  and  case-hardened,  or  from 
tool  steel  and  left  soft ;  or,  if  the  latter  steel  is 
used,  they  may  be  hardened  and  carefully  tern- 


80  MOTOR    BICYCLE    BUILDING. 

pered,  the  centre  parts  being  let  down  to  a  brown 
and  the  ends  right  down  or  to  a  blue.  In  the 
latter  case,  the  hardening  requires  to  be  very 
carefully  done  and  not  left  too  hard,  or  there  is 
a  chance  of  fracture. 

Pulley-side  Main  Shaft.— For  the  shaft  (Fig. 
66),  cut  off  -If  in.  of  if -in.  or  1-in.  stuff.  The  dead 
length  finished  will  be  4|  in.,  so  that  if  it  is  cut 
off  on  the  anvil,  allowance  must  be  made  for 
truing  up  the  ends.  Centre  the  ends,  and  drill 
up  with  the  centre  drill  to  the  same  angle  as  the 
lathe  centres.  See  that  the  rest  is  set  to  turn  dead 
parallel,  and  turn  up  |  in.  from  end  to  end,  to 
fit  the  main  crank  case  bush  nicely,  without  shake, 
but  a  free  fit.  Turn  down  one  end  to  f  in.  for 
-j9^  in.,  and  \  in.  from  this  shoulder  scribe  a  fine 
line  round  the  |-in.  diameter,  and  2^^  in.  from 
this  scribe  another  line  round — these  are  for 
guides  to  which  to  turn  the  end  of  the  taper  part; 
ii  in.  from  this  last  line  turn  down  f  in.  to  the 
end.  These  f-in.  ends  require  screwing  twrenty- 
six  threads  per  inch,  to  fit  tightly  suitable  nuts, 
which  should  be  5  in.  thick.  The  rest  should  be 
set  to  turn  the  same  taper  as  was  used  to  bore 
out  the  taper  holes  in  the  flywheels.  Test  the 
shaft  ends  in  the  flywheel  holes  with  red-lead, 
until  the  taper  end  of  the  shaft  is  seen  to  touch 
from  end  to  end. 

Short  or  Gear-side  Main  Shaft. — The  short  or 
gear-side  shaft  (Fig.  67)  is  treated  in  the  same 
way,  the  plain  end,  to  take  the  small  gear  wheel, 
being  f  in.  in  diameter  by  f  in.  long.  It  is  well 
to  leave  the  final  size  of  this  end  until  the  gear 
wheel  is  bored.  The  plain  parallel  part  of  this 
shaft  is  l^f-  in.,  the  taper  part  A  in.,  and  the 
screwed  part  -^  in.  The  crank  pin  (Fig.  68)  is 
turned  from  a  piece  of|J-in.  or  |-in.  stuff;  the 
diameter  is  f  in.,  to  fit  the  large  end  of  the  con- 
necting-rod bush,  and  it  is  3T3^in.  long  over  all. 
The  two  ends  are  f  in.  by  ^  in.,  screwed  twenty- 


MAKING    A    3§-H.P.    PETROL    MOTOR.  81 

six  threads  per  inch;  the  taper  parts  are  i  in. 
long,  and  the  parallel  parts  If  in.  The  taper 
parts  of  all  three  shafts  must  be  a  perfect  fit  in 
their  respective  holes  in  the  flywheels,  and  care 
must  be  taken  that  the  shoulders  at  the  end  of 
the  threaded  parts  do  not  come  right  through  the 
holes  in  the  flywheels.  When  the  shafts  are  right 
home,  and  the  nuts  screwed  up  hard,  the  face 
of  the  nuts  should  bed  against  the  flywheel  before 
it  touches  the  shoulder  on  the  shaft  end  by  about 
¥V  in.  Should  the  nut  face  touch  the  shaft  shoul- 
der before  it  beds  against  the  flywheel,  it  will 
not  be  long  before  the  flywheels  are  loose  on  their 
shafts  and  out  of  truth.  In  making  these  three 
shafts  it  will,  of  course,  be  best  and  quickest  to 


V* 
Fig.  69.— Half-time  Shaft.  Fig.  70.— Tappet  Rod. 

turn  all  the  taper  parts  at  one  setting  of  the 
rest,  and  also  to  do  all  the  screwing  at  one  time. 

Half-time  Shaft.— The  half-time  shaft  (Fig. 
69)  may  as  well  be  made  at  this  stage,  though  the 
large  gear  wheel  and  exhaust  cam  should  be 
finished  first,  so  as  to  be  able  to  get  the  shaft  a 
good  tight  fit.  The  finished  size  is  2|  in.  over  all. 
The  main  part  is  J  in.  in  diameter  by  If  in.  long, 
to  fit  tightly  the  bore  of  the  gear  wheel  and  ex- 
haust cam.  The  f-in.  part  is  1  in.  long,  to  fit  the 
bush  in  the  gear  cover  of  the  crank  case  freely. 

Tappet  Hod.—  The  tappet  rod  (Fig.  70)  is 
turned  from  a  piece  of  tool  steel,  and  need  only 
be  hardened  on  the  extreme  end  (the  round  end). 
It  is  T7g-  in.  in  diameter,  wTith  the  end  nicely 
rounded  and  smoothed  off.  The  top  end  is  turned 
down  to  f  in.  for  J  in.,  to  take  the  circular  plate 
(Fig.  71),  which  should  be  a  piece  of  mild  steel 
F 


MOTOR    BICYCLE    BUILDING. 


^  in.  thick  by  lg  in.  in  diameter,  case-hardened, 
and  firmly  riveted  on  the  tappet  rod.  This  rod 
should  fit  the  tappet  guide  (Figs.  56  and  57,  p. 
73)  without  shake. 

Gudgeon  Pin. — The  gudgeon  pin  (Fig.  72)  may 
be  a  piece  of  tool  steel  3^  in.  long  by  i  in.  in 
diameter.  It  is  turned  to  fit  the  piston  tightly, 
the  piston  having  been  reamered  out  slightly 
taper;  and  the  pin  must  have  a  corresponding 
amount  of  taper.  It  should  be  a  light  driving 
tit,  so  that  the  small  end  does  not  come  quite  flush 
with  the  outside  of  the  piston  by  about  ^  in- 


Fig.  71.— Circular  Plate  of  Tappet 
Bod. 


Fig.  72.— Gudgeon  Pin. 

The  large  end  is  then  covered  with  a  brass  washer 
^  in.  in.  diameter,  which  will  prevent  the  pin 
working  back  and  scoring  the  cylinder  walls. 
This  method  of  fixing  the  gudgeon  pin,  though 
simple,  has  been  found  to  be  very  effective;  but 
it  is  most  important  that  it  should  be  a  good  tight 
fit  in  the  piston,  and  fitted  with  a  slight  degree 
of  taper.  Set  pins,  however  well  fitted  and  se- 
cured by  split  pins,  etc.,  are  never  reliable. 

It  will  probably  be  found,  upon  trying  the 
gudgeon  pin  in  the  connecting-rod  bush,  that  it 
is  too  tight  a  fit.  If  so,  the  bush  should  be 
reamered  out  until  the  pin  is  a  good  fit  without 


MAKING    A    3|-H.P.    PETROL    MOTOR.  83 

shake.  A  piece  of  brown  paper  on  one  side  of 
the  reamer  will  cause  it  to  cut  a  shade  larger  than 
if  used  without.  The  pin  should  be  hardened, 
and  let  down  to  brown  in  the  centre  and  blue 
at  the  ends.  In  hardening,  do  not  get  the  steel 
so  hot  as  to  scale,  or  the  fit  will  be  upset,  and  dip 
quite  straight  in  the  water  end  on.  In  fitting  the 
gudgeon  pin  to  the  piston,  be  sure  that  both  ends 
are  equally  tight  in  the  piston  holes,  or  it  will 
soon  work  loose.  Do  not  harden  the  shafts  until 
the  keyways  have  been  cut  and  the  crank  case 
with  the  flywheels  have  been  fitted  together  and 
assembled. 

Cutting  Keyways  in  Shafts.—  A  simple  and  at 
the  same  time  thoroughly  efficient  method  of  cut- 
ting the  keyways  in  the  various  shafts  will  now  be 


Fig.  73. 
Figs.  73  and  74. — Tool  for  Cutting  Keyways  in  Lathe. 

given.  All  that  has  to  be  made,  for  cutting  key- 
ways  in  an  ordinary  slide-rest  lathe,  is  the  tool 
shown  at  Figs.  73  and  74.  It  is  turned  from  a 
piece  of  f-in.  or  £-in.  tool  steel,  the  end  being 
reduced  to  a  diameter  corresponding  to  the  width 
of  the  keyway  to  be  cut.  This  portion  of  the  tool, 
for  the  present  purpose,  will  be  ^  in.  in  diameter 
by  |  in.  long ;  it  is  as  well  to  keep  this  part  short, 
to  prevent  springing  of  the  tool  as  far  as  possible. 
The  reduced  part  is  then  filed  on  each  side  until  it 
is  ^2  in.  thick ;  the  sides  are  backed  off  slightly, 
and  the  two  cutting  edges  filed  as  shown.  The 
end  is  then  hardened  in  the  usual  way,  and  let 
down  to  a  dark  straw  colour  at  the  cutting  edges. 
The  tool  is  next  mounted  in  the  lathe  chuck  to  run 
true,  and  the  shaft  to  be  cut  is  clamped  in  the 
tool-holder  of  the  slide-rest,  at  right  angles  to  the 


84  MOTOR    BICYCLE    BUILDING. 

tool,  and  with  its  axis  perfectly  level  with  the 
lathe  centres.  The  shaft  is  fed  up  to  the  cutter  by 
means  of  the  slide-rest,  a  start  being  made  at  the 
inner  or  rounded  end  of  the  keyway ;  the  top  slide 
is  then  worked  for  the  required  length  of  the  key- 
way.  Not  more  than  -£f  in.  in  depth  should  be 
taken  at  one  cut,  or  the  tool  may  break.  Pro- 
vided the  shaft  is  set  true  in  all  directions  in  the 
tool  post,  and  the  cutter  is  sharp,  a  perfect  key- 
way  is  the  result,  equal  in  every  respect  to  one  cut 
in  a  keyway  or  slotting  machine.  The  various 
keys  may  be  fitted  by  filing  flats  on  the  shafts  for 
the  keys,  but  this  method,  unless  the  fitting  is 
very  well  done,  is  not  recommended.  The  simple 
method  described  above  will  be  found  much  more 
reliable,  and,  of  course,  is  quicker  once  the  tool 
has  been  made.  Besides  which,  the  tool  will  cut 
other  keyways  of  the  same  width. 

All  the  keyways  in  the  two  main  shafts,  crank 
pin,  and  half-time  shaft  are  of  the  same  width  and 
depth,  that  is,  i  in.  by  J  in.  The  length  of  the 
keyway  in  the  half-time  shaft  is  1  in.  ;  the  others 
are  cut  as  long  as  possible.  The  keyways  in  the 
flywheels,  gear  wheel,  and  exhaust  cam  should  be 
filed,  if  a  slotting  machine  is  not  available  ;  they 
must  be  quite  flat  and  straight,  with  no  taper. 
In  fitting  the  keys,  which  should  be  made  from 
cast  steel,  file  on  the  sides  first,  to  fit  the  width  of 
the  keyways  ;  then  true  up  one  face  perfectly  flat, 
and  fit  the  key  carefully  in  its  place  by  filing  on 
the  other  face  only.  Do  not  cut  off  the  key  until 
it  has  been  perfectly  fitted,  and  this  is  not  at- 
tained until  the  key  beds  on  its  seating  from  end 
to  end  on  both  sides.  The  fitting  of  all  keys  on  a 
motor  of  this  kind  calls  for  special  care,  as  a 
wheel  fitted  to  a  shaft  with  anything  but  first-class 
workmanship  is  sure  to  work  loose  sooner  or  later. 

Engine  Belt  Pulley.- — Fig.  75  is  a  section  of  the 
•engine  belt  pulley,  which  is  an  iron  casting.  The 
pattern  should  be  made  in  two  parts,  parting  at 


MAKING    A    3£-H.P.    PETROL    MOTOR.  85 

the  bottom  of  the  belt  groove.  A  core  box  is  not 
absolutely  necessary,  as  the  inside  can  be  left 
parallel  and  the  recessed  portion  turned  out  of 
the  casting.  This  reces&ed  part  is  for  retaining 
any  oil  which  may  work  out  of  the  crank  case 
through  the  main  bearing,  and  prevent  it  being 


Fig.  75.— Section  of  Engine  Pulley. 

thrown  over  the  outside  of  the  engine.  A  drain- 
hole  is  drilled,  tapped,  and  fitted  with  a  |-in. 
Whitworth  screw.  If  this  screw  is  removed  from 
time  to  time,  and  any  oil  which  has  accumulated 
drained  off,  this  side  of  the  engine  at  any  rate  will 
be  kept  free  from  oil.  Chuck  the  casting  in  the 
jaw  chuck,  large  side  outwards  ;  bore  a  f-in.  hole, 


86  MOTOR   BICYCLE    BUILDING. 

and  turn  out  3  degrees  taper,  to  suit  the  taper  of 
the  main  shaft.  Turn  up  the  outer  edge  of  the 
rim  4|  in.  in  diameter ;  and  turn  out  the  belt 
groove  28  degrees,  f  in.  wide  at  the  top.  The 
bottom  of  the  belt  groove  is  2f  in.  in  diameter. 
Clear  up  the  inside,  and  turn  out  the  recessed 
part.  The  back  should  be  1|  in.  from  the  face. 
The  face  of  the  boss  for  the  lock-nut  to  bed  against 
may  be  trued  up  with  a  hook  tool  at  this  setting, 
the  length  of  the  boss  for  the  shaft  being  f  in. 
through. 

The  casting  may  now  be  mounted  on  its  shaft, 
and  the  remainder  of  the  outside  turned  up  on  the 
lathe  centres.  This  pulley  is  designed  for  a  |-in. 
belt,  which  is  strong  enough  if  the  engine  is  to  be 


Fig.  76.— Locking  Plate. 

used  for  a  single  cycle  ;  but  if  for  use  with  a 
trailer,  £  in.  is  advisable,  while  for  tri-car  work  a 
1-in.  belt  is  required.  For  the  1-in.  belt  the  cast- 
ing must  be  i  in.  to  T3g  in.  wider  at  the  belt  groove, 
but  the  present  casting  will  turn  out  for  the  f-in. 
size.  A  keyway  ^  in.  wide  by  ^  in.  deep  must  be 
cut  the  length  of  the  bore. 

Securing  Pulley  to  Shaft. — This  pulley  is  se- 
cured on  its  shaft  by  two  J-in.  thick  lock-nuts, 
screwed  to  fit  the  f-in.  by  26  threads  at  the  shaft 
end,  besides  the  key.  An  alternative  method  of 
fixing  the  engine  pulley  to  the  shaft  is  to  screw  the 
end  of  the  shaft  with  a  right-hand  thread,  4  in-  by 
26  threads,  and  the  pulley  bore  to  suit,  in  place  of 
the  plain  taper  and  key,  and  fit  a  left-hand  thread 
lock-nut,  f  in.  by  26  threads  to  the  inch.  This 


MAKING    A    3i-H.P.    PETROL    MOTOR.  87 

makes  a  reliable  fixing,  but  the  pulley  is  some- 
times very  difficult  to  remove  if  it  gets  jammed  on 
the  thread. 

Pinning  Lock-nut  to  Shaft. — The  lock-nuts 
which  secure  the  two  main  shaft  ends  to  the  fly- 
wheel, and  one  end  of  the  crank  pin,  may  be 
secured  permanently  by  drilling  a  |-in.  hole  half  in 
the  nut  and  half  in  the  end  of  the  shaft,  and  then 
driving  in  a  pin  which  is  T^  in.  shorter  than  the 
hole  is  deep,  and  burring  the  edge  of  the  hole  over 
the  pin.  The  drilling  must  be  done  before  the 
shafts  are  hardened,  the  pinning  being  the  last 
operation  of  all  when  finally  assembling. 

Safety  Lock  for  Crank  Pin  Lock-nut.— The 
lock-nut  on  the  other  end  of  the  crank  pin  will  re- 


Fig.  77.          Fig.  78. 
Figs.  77  and  78.— =Exhaust  Cam. 

quire  a  safety  lock,  but  it  should  be  of  such  a 
nature  that  will  allow  of  removal  for  future  re- 
pairs, etc.  Such  a  lock  may  be  made  by  fitting 
a  sheet-steel  plate  cut  out  of  No.  15  or  No.  16 
gauge  sheet,  as  shown  at  Fig.  76.  This  is  slipped 
on  over  the  lock-nut  after  it  has  been  tightened 
right  up,  and  the  small  end  secured  to  the  face  of 
the  flywheel  with  a  small  screw  tapped  into  the 
flywheel,  which  must  be  a  good  tight  fit  on  the 
thread,  and  have  a  good  strong  head. 

Exhaust  Cam. — The  exhaust  cam  (Figs.  77  and 
78)  is  made  from  tool  steel  carefully  hardened  and 
tempered.  The  dimensions  are — bore,  J  in.,  to  fit 
tight  on  the  half-time  shaft;  diameter,  1^  jn 


MOTOR    BICYCLE    BUILDING. 


with  a  J-in.  lift ;  it  is  T96-  in.  wide,  and  keywayed 
i  in.  by  J  in.  Harden  right  out,  polish,  and  1st 
down  to  a  brown  on  the  wearing  surface,  and  get 
the  inside  as  low  as  possible  ;  this  may  be  done  by 
making  an  iron  rod  very  hot  and  inserting  it  in  the 
hole,  letting  the  hot  rod  bear  most  on  the  thick 
side  of  the  cam,  or  the  thin  side  will  be  let  down 
too  low  before  the  thick  or  lift  side  is  low  enough. 
Gear  Wheels. — Plans  and  sections  of  the  largo 
and  small  gear  wheels  are  shown  at  Figs.  79  to  82; 
these  actuate  the  exhaust  and  ignition  cams  on 
the  half-time  shaft.  The  large  gear  wheel  may  be 


Fig.  79.  Fig.  80. 

Figs.  79  and  80.— Large  Gear  Wheel. 

in  phosphor-bronze,  and  has  32  teeth  ;  it  is  2  in. 
in  diameter  on  the  pitch  line,  2j  in.  in  diameter 
over  all,  has  a  i-in.  hole  to  fit  tight  the  half-time 
shaft,  and  is  |  in.  thick  on  the  face  of  the  teeth. 
The  small  gear  wheel  is  of  good  tough,  mild  steel, 
case-hardened.  It  has  16  teeth,  is  1  in.  in  diameter 
on  the  pitch  line,  Ij  in.  in  diameter  over  all,  has  a 
f-in.  hole  to  fit  tight  the  end  of  the  main  shaft, 
and  is  f  in.  wide  on  the  face  of  the  teeth.  It 
should  be  keywayed  only  TV  in.  deep  by  i  in.  wide. 
If  the  keyway  is  cut  any  deeper  than  this,  the 
wheel  will  not  be  strong  enough,  and  will  be  liable 
to  burst  when  the  key  is  fitted  up.  In  the  absence 
of  proper  facilities  for  gear-cutting,  this  part  of 


MAKING    A    3J-H.P.    PETROL    MOTOR. 


the  work  must  be  put  out  to  be  done.  The  blanks 
can  be  bored  and  turned  to  the  sizes  given,  and 
sent  to  a  firm  who  make  a  speciality  of  this  class 
of  work ;  or  they  may  be  purchased  finished  from 
most  dealers  in  motor  parts.  If  the  cutting  is 
done  at  home,  two  cutters  will  be  required,  one 
for  the  driven  wheel  and  one  for  the  driver,  the 
shape  of  tooth  being  different  in  each.  If  wheels 
of  exactly  the  same  number  of  teeth  cannot  be 
purchased,  they  may  have  30  and  15  or  28  and  14, 
so  long  as  they  are  the  same  diameter  on  the  pitch 
line.  It  is  not  advisable  to  have  finer  teeth  than 
would  be  in  wheels  of  32  and  16,  of  these  pitch 


^_- 


igr.  si.  Fig.  82. 

Figs.  81  and  82.— Small  Gear  Wheel. 

diameters,  as  they  would  be  weaker;  and  coarser 
than  28,  and  14  would  be  too  large  for  the  purpose. 
In  fitting  up  the  large  gear  wheel  and  exhaust 
cam  to  the  half-time  shaft,  the  gear  wheel  is  fitted 
with  one  face  level  with  the  shoulder  at  the  finish 
of  the  f-in.  part,  and  the  exhaust  cam  behind  it. 

Cutting  Keyway  in  Large  Gear  Wheel.- — Cut- 
ting the  keyway  in  the  large  gear  wheel  should 
bs  left  until  the  parts  are  assembled,  as  the  timing 
of  the  exhaust  valve  lift  and  closing  can  be  set 
to  a  nicety  by  shifting  this  wheel  a  trifle  on  its 
shaft.  It  will  here  be  found  advantageous  to 
have  the  wheel  a  good  tight  fit  on  the  shaft,  as 
the  friction  will  keep  the  wheel  in  position  whilst 
the  timing  is  done.  The  position  of  the  keyway 
can  then  be  marked  accurately  whilst  in  place. 

Induction    or    Inlet    Pipe. — The   induction     or 


90  MOTOR    BICYCLE    BUILDING. 

inlet  pipe  from  the  engine  to  the  carburettor  is 
illustrated  at  Fig.  83.  This  is  made  from  Ig-in. 
No.  16  gauge  weldless  steel  tube  bent  to  the  shape 
shown.  About  10  in.  is  actually  taken  up  in  the 
bend  illustrated,  but  a  length  of  at  least  1  ft.  4  in. 
or  1  ft.  6  in.  will  be  required  for  the  purpose,  as 
the  bends  finish  so  near  the  ends.  The  tube 
should  be  rammed  as  tight  as  possible  with  fine 
dry  sand,  and  the  ends  stopped  with  metal  plugs. 
The  tube  is  heated  2  in.  or  3  in.  at  a  time  to  a 
good  bright  heat,  and  bent  to  a  radius  of  If  in. 
The  two  ends  should  be  quite  parallel  with  each 
other,  or  the  carburettor  will  not  be  upright  when 
fitted  to  the  engine.  A  steel  washer  or  collar, 
turned  all  over,  is  brazed  to  one  end,  the  union 
nut  holding  the  pipe  securely  to  the  engine  by 
this  collar.  The  other  end  of  the  pipe  will  be 
fitted  with  a  suitable  union  to  fit  the  carburettor 
connection.  The  type  of  this  connection  will  de- 
pend upon  the  size  and  pattern  of  carburettor 
used.  A  suitable  carburettor  for  the  engine  will 
be  a  Longuemare,  Model  H,  or  the  device  described 
in  the  next  chapter.  It  will  be  advisable  to  pur- 
chase this  fitting  instead  of  attempting  to  make 
it,  unless  the  worker  is  very  skilful. 

Contact-breaker. — The  type  of  contact-breaker 
to  be  used  has  now  to  be  chosen.  This  may  be  of 
the  wipe  type  with  a  trembler  coil,  or  a  make- 
and-break  with  a  plain  coil.  Opinions  are 
divided  as  to  which  is  preferable  for  a  motor 
cycle  ignition.  With  a  wipe  contact  and  trembler 
coil  easy  starting  is  facilitated,  and  risk  of  miss- 
fires  is  lessened,  but  the  engine  will  not  attain  the 
high  rate  of  speed  that  it  will  with  a  make- 
and-break  and  a  plain  coil.  Neither  can  the 
timing  be  set  to  the  same  degree  of  nicety  as 
with  the  make-and-break.  Against  the  latter  sys- 
tem there  is  frequent  trimming  up  and  adjust- 
ment of  platinum  contact  points,  and  sometimes 
difficulty  in  starting,  unless  these  two  items  aro 


MAKING    A    3.>H.P.    PETROL    MOTOR.          91 

perfect.  For  ordinary  purposes,  the  wipe  con- 
tact and  trembler  coil  are  preferable.  Which- 
ever system  is  adopted,  the  contact-breaker  will  be 
purchased  ready-made  with  ignition  cam  or  wipe 
sector.  This  cam  or  sector  will  be  fitted  on  the 
small  end  of  the  half-time  shaft. 

Assembling  the  Engine.— With  all  the  compo- 
nent parts  made  and  finished,  the  final  assembling 
of  the  engine  may  now  be  started.  The  two  main 
shafts  should  be  fitted  to  their  respective  flywheels, 
the  nuts  screwed  right  home,  and  secured  with 
small  pegs  in  the  nuts  and  shaft  ends.  One  half 
(the  gear-side  half  for  preference)  of  the  crank 


Fig.  83.— Inlet  Tube  from  Carburettor. 

pin  should  be  served  in  a  similar  manner.  The 
rings  should  be  fitted  to  the  piston  grooves,  and 
the  piston  to  the  connecting-rod  by  the  gudgeon 
pin,  which  must  be  tapped  in  far  enough  to  allow 
of  the  i-in.  brass  covering  washer  clearing  the 
cylinder  walls  when  the  piston  is  in,  but  not  so 
far  that  the  opposite  end  will  touch  the  opposite 
side  of  the  cylinder. 

The  connecting-rod  may  now  be  slipped  over 
the  crank  pin,  and  the  flywheels  fitted  together  by 
the  other  end  of  the  crank  pin ;  the  nut  is  then 
tightened,  and  the  flywheels  tested  between  the 


92  MOTOR    BICYCLE    BUILDING. 

lathe  centres  for  truth.  If  out  of  Uuth,  some  part 
has  been  put  together  improperly,  or  one  of  the 
taper  ends  of  the  shafts  may  have  some  grit  or 
dirt  on  it,  thus  preventing  a  true  fitting  of  the 
surfaces.  If  true,  lock  the  nut  as  tight  as  it  will 
go,  and  fit  on  the  sheet-steel  locking  device  (Fig. 
76,  p.  86). 

Balancing  the  Flywheels. — It  will  be  found  that 
the  balance  weights  cast  on  the  flywheels  are  not 
sufficient  to  balance  the  weight  of  the  crank  pin, 
connecting-rod,  and  about  half  the  weight  of  the 
piston  ;  therefore  §-in.  holes  should  be  drilled  in 
the  rim  of  the  flywheels,  on  the  crank  pin  side, 
to  balance  this.  A  weight  equal  to  the  above-men- 
tioned fittings  may  be  suspended  from  the  crank, 
whilst  flywheels  are  lightly  held  between  the  cen- 
tres of  the  lathe.  If  sufficient  metal  cannot  be 
taken  out  of  the  rims  in  this  manner,  without 
unduly  weakening  them,  holes  can  be  drilled  in 
the  opposite  side  of  the  rims  (balance-weight 
side),  and  filled  with  lead.  To  prevent  any 
possibility  of  this  lead  working  loose,  drill  the 
holes  through  the  side  of  the  rim,  and  then 
drill  other  holes  from  the  outer  edge  to  meet  the 
first;  this  will  form  T-shaped  openings,  into 
which  the  lead  may  be  cast  without  fear  of  its 
coming  out.  Fit  the  two  halves  of  the  crank  case 
together,  with  the  flywheels  in  place. 

Bolting  up  Crank  Case.—  The  air  valve,  oil 
connection,  and  drain  plug  all  being  fitted,  sec 
that  the  edges  of  the  case  are  quite  clean  and 
coated  with  red-lead  and  oil.  Bring  the  halves 
together.  Insert  two  of  the  f-in.  bolts,  which  hold 
the  halves  together,  at  opposite  points,  screw  up, 
arid  test  the  flywheels  for  freedom  of  running  be- 
fore proceeding  further.  If  satisfactory,  insert 
the  rest  of  the  f-in.  bolts  and  screw  up. 

Fitting  Cylinder  to  Crank  Case.— The  cylinder 
can  now  be  fitted  on  to  the  crank  case.  See  that 
the  surfaces  that  come  together  are  perfectly  clean. 


MAKING    A    3^-H.P.    PETROL    MOTOR.  93 

Cut  out  a  stout  brown-paper  washer  to  go  between 
the  cylinder  flange  and  the  top  of  the  crank  case. 
Bolt  down  equally,  and  test  for  free  working;  by 
fastening  a  lathe  carrier  on  to  the  end  of  the 
shaft,  the  flywheels  can  be  revolved.  If  this  does 
not  work  so  free  as  it  should,  making  due  allow- 
ance for  friction  of  the  piston  rings,  etc.,  remove 
and  find  out  the  cause. 

Completing  the  Assembling. — It  should  be  men- 
tioned that  all  parts  are  to  be  oiled,  as  they  go 
together ;  and  in  fitting  piston  rings,  see  that  the 
joints  are  equally  divided.  Key  on  the  16-tooth 
wheel  to  the  end  of  the  main  shaft  when  every- 
thing works  free.  The  tappet-rod  guide  should  be 
screwed  ur>  tight  in  the  gear-cover  top,  and  the 
half-time  shaft  tried  in  its  place  with  the  gear 
cover  on.  Key  on  the  exhaust  valve  cam  to  its 
shaft,  tap  on  the  large  gear  wheel  temporarily, 
fit  up  the  exhaust  valve,  put  the  gear  cover  on, 
and  slip  in  the  tappet  rod.  The  end  of  the  ex- 
haust-valve stem  should  come  within  -^  in.  of  the 
plate  on  the  tappet  rod,  when  the  valve  is  right 
down  on  its  seating  and  the  cam  is  out  of  opera- 
tion. When  this  has  been  so  arranged,  harden  the 
end  stem  of  the  valve. 

Timing  the  Engine. — The  timing  is  a  very  im- 
portant operation,  and  may  now  be  attended  to. 
Get  a  piece  of  stout  wire  that  will  pass  through 
the  small  hole  drilled  in  the  top  of  the  cylinder, 
and  on  this  wire  make  a  mark  level  with  the  top 
of  the  cylinder  when  the  piston  is  at  its  highest 
point  in  the  cylinder,  the  end  of  the  wire  resting 
on  the  top  of  the  piston.  Turn  the  main  shaft 
(by  the  carrier)  until  the  piston  has  descended 
to  its  lowest  point,  then  make  another  mark  on 
the  wire  in  the  same  way  as  before.  It  is  now 
possible  to  tell  to  a  nicety  when  the  piston  is  at 
its  highest  and  lowest  point  in  the  cylinder.  Now 
so  arrange  the  large  gear  wheel  on  the  half-time 
shaft  that  the  cam  will  cause  the  exhaust  valve 


MOTOR    BICYCLE    BUILDING. 


just  to  start  opening  when  the  piston  has  de- 
scended four-fifths  of  its  stroke  in  the  cylinder, 
and  the  valve  shuts  dead  on  its  seating  upon  the 
completion  of  the  next  up  stroke.  The  meshing 
of  the  gear  wheel  teeth  must  be  altered  until  the 
desired  effect  is  obtained,  when  the  exact  position 
for  the  keyway  on  the  large  wheel  can  be  marked 
and  cut  and  keyed  up.  It  may  be  necessary  to 
alter  the  shape  of  the  cam  slightly  (by  grinding, 
if  it  has  been  already  hardened)  to  bring  about 
the  desired  effect. 


Fig.  84.  Jf'i<r.  85. 

Figs.  84  and  85.— Bottom  Plate  of  Silencer. 

Timing  the  Ignition. — The  timing  of  the  ig- 
nition is  the  next  operation.  The  ignition  cam 
must  be  fixed  to  the  end  of  the  half-time  shaft 
in  such  a  position  that  the  spark  will  pass  when 
the  piston  is  at  the  top  of  its  compression  stroke, 
with  the  contact-breaker  case  or  rocker  in  its  mid- 
way position.  This  will  allow  for  retarding  and 
advancing  the  spark  to  the  desired  amount.  It 
must  be  noted  that  the  actions  of  a  wipe  contact 
and  a  make-and-break  are  different  in  this  respect 
— that  whereas  with  the  wipe  the  spark  will  pass 
at  the  plug  points  immediately  the  brass  section 
of  the  fibre  cam  touches  the  block  on  the  spring 
^wiper,  with  the  make-and-break  the  spark  does 


MAKING    A    3|-H.P.    PETROL    MOTOR.  95 

not  pass  when  the  platinum  points  are  brought 
together  by  the  action  of  the  ignition  cam,  but  at 
the  break — that  is,  immediately  the  cam  allows 
the  points  to  spring  apart.  Due  allowance  for 
this  must  therefore  be  made  when  fitting  up  either 
of  these  systems.  It  only  remains  to  fit  in  the 
inlet  valve,  fit  on  the  belt  pulley,  and  fill  in  the 
small  hole  in  the  cylinder  head  with  its  screw,  and 
the  engine  is  complete,  less  the  silencer. 

Silencer. — A    simple    but    thoroughly    effective 
silencer   has   been    designed   for   this   engine,    the 


Fig.  86.  Fig.  87. 

Figs.  86  and  87.— Top  Plate  of  Silencer. 

component  parts  being  shown  at  Figs.  84  to  89. 
The  outside  cylinder  is  not  shown,  as  it  needs  no- 
illustration  to  make  it  clear.  It  is  simply  a 
plain  sheet-iron  cylinder,  10  in.  by  3  in.,  outside 
measurement,  and  about  No.  18  gauge.  It  can 
be  joined  as  stove  piping  is  joined,  by  simply  lap- 
ping the  edges  over  each  other  and  hammering 
flat  on  a  mandrel,  or  the  edges  may  overlap  i  in. 
and  be  riveted  together  with  small  iron  rivets. 
Figs.  84  and  85  show  the  bottom  end,  and  Figs. 
86  and  87  the  top.  These  are  malleable  iron  cast- 
ings, turned  to  the  dimensions  given.  The  top 
flange  is  screwed  for  1|  in.,  26  threads  to  the  inch, 


96  MOTOR    BICYCLE    BUILDING. 

and  drilled  with  two  j-in.  holes,  1^  in.  from  the 
centre.  The  bottom  flange  is  drilled  with  two  g-in. 
holes  |  in.  from  the  centre,  and  two  s-in.  holes  to 
correspond  with  those  in  the  top  flange.  They 
are  turned  to  fit  tight  over  the  10-in.  by  3-in. 


Fig.  88.— Tube  for  Silencer. 

cylinder.  Two  f-in.  by  No.  16  gauge  weldless 
tubes,  9|  in.  long,  are  stopped  at  one  end  by  hav- 
ing two  washers  brazed  in,  and  seven  rows  of 
TV-in.  holes  (about  eighteen  to  the  row)  are  drilled 
in  the  stopped  ends  (see  Fig.  88).  The  open  ends 
of  these  tubes  are  knocked  tight  into  the  |-in. 
holes  in  the  bottom  flange  and  brazed.  The  whole 
is  held  together  by  the  two  ^-in.  pins  (Fig.  89), 
which  are  lOf  in.  long  and  screwed  at  the  ends 
4-in.  Whitworth,  and  fitted  with  a  nut  at  each 
end.  The  nuts  must  be  a  good  tight  fit  on  the 
thread — in  fact  two  of  them  can  be  riveted  over. 


I03/i  - 
-Pin  or  Bolt  for  Silencer. 

Exhaust  Pipe. — The  exhaust  tube  to  connect 
the  silencer  to  the  engine  will  be  of  weldless  tube, 
l£  in.  by  No.  16  gauge  screwed  to  suit.  The  length 
and  shape  will  depend  upon  the  positioh  in  which 
the  silencer  is  fixed. 


CHAPTER    V. 

SPRAY    CARBURETTOR   FOR   83  H.  P.    MOTOR. 

MOST  readers  of  this  book  will  be  familiar  with 
the  function  of  a  carburettor,  and  will  know  that 
originally  the  carburettor  was  of  the  surface  type 
—that  is,  the  air  on  its  way  to  the  engine  cylinder 
was  carburetted  (saturated  with  petrol  vapour) 
by  being  obliged  to  bubble  up  through  petrol  con- 
tained in  a  suitable  vessel.  For  years,  now,  the 
spray  carburettor  has  been  in  general  use,  al- 
though quite  occasionally  the  surface  carburettor 
can  still  be  found  doing  good  work. 

A  carburettor  is,  in  simple  words,  a  gas-maker. 
The  carburettor's  air  intake  pipe  often  has  a  bell- 
mouth  so  as  to  collect,  as  it  were,  the  air  from 
the  surface  of  the  motor  head  and  cylinder.  The 
air  being  so  warmed  assists  the  action  of  the  car- 
burettor in  cold  weather,  or  when  petrol  of  greater 
than  ordinary  density  is  being  used.  It  will  be 
understood  that  the  air  is  sucked  into  the  car- 
burettor on  the  first  outward  stroke  of  the  piston 
in  the  engine's  four^etroke-cycle.  As  the  air  rushes 
up  past  a  nozzle,  which  is  in  connection  with  the 
petrol  supply,  a  thin  stream  of  petrol  is  caused 
to  be  ejected  from  the  nozzle  into  the  vaporising 
chamber.  In  many  designs  of  carburettor,  the 
stream  of  petrol  impinges  on  a  cone  or  mushroom, 
which  assists  in  breaking  up  mechanically  the 
drops  of  petrol.  The  air  in  motion  has  a  great 
capacity  for  absorbing  the  petrol  particles,  and 
as  it  passes  onward  to  the  cylinder,  the  peculiar 
mechanical  construction  of  the  upper  part  of  the 
carburettor,  and  possibly  the  heat  of  the  various 
parts,  assist  in  making  the  mixture  of  air  and 
G 


98  MOTOR    BICYCLE    BUILDING. 

petrol  still  more  intimate,  until  when  the  mixture 
reaches  the  engine  cylinder  it  may  be  regarded, 
for  the  moment  only,  as  a  true  gas.  The  ignition 
and  the  consequent  expansion  of  the  combustible 
gas  in  the  engine  cylinder  provides  the  working 
stroke,  which  gives  impulse  to  the  crankshaft  and 
flywheel. 

It  is  usual  to  provide  a  carburettor  with  what 
is  known  as  a  float-feed,  this  being  a  simple  de- 
vice by  means  of  which  the  ingress  of  the  petrol 
from  the  petrol  tank  is  regulated  by  a  float,  which 
opens  or  clones  the  petrol  inlet  valve  according 
to  the  quantity  of  petrol  in  the  float  chamber, 
between  which  and  the  spraying  nozzle  alluded  to 
above  there  is  a  tubular  connection.  This  float 
device  prevents  flooding  of  the  carburettor,  but 
most  carburettors  have  projecting  from  them  a 
small  rod,  by  means  of  which  the  action  of  the 
float  can  be  momentarily  suspended  for  conveni- 
ence in  obtaining  a  rich  mixture  when  starting 
the  engine. 

The  simple  carburettor  illustrated  and  described 
in  this  chapter  has  been  in  use  for  some  two  or 
three  years,  and  has  proved  very  efficient.  It  has 
been  used  on  engines  of  from  2  h.p.  to  3i  h.p., 
and  works  equally  well  with  any  engine  within 
this  range,  and  would  no  doubt  be  quite  suitable 
for  one  of  4  h.p.  to  4j  h.p.  by  adjusting  the  petrol 
tap  to  pass  more  petrol.  Fig.  90  is  a  full-size 
sectional  view  of  the  complete  carburettor  and 
throttle  valve.  All  the  illustrations  in  this  chap- 
ter are  reproduced  full  size. 

The  whole  of  the  castings  are  brass,  the  needle 
valve  A  is  of  steel,  and  the  cone  piece  B  of  fine 
copper  gauze. 

The  top  part,  which  contains  the  throttle  valve, 
can  first  be  taken  in  hand.  The  casting  is  chucked 
by  the  small  end,  and  bored  right  through  f  in. 
diameter,  the  large  end  being  bored  out  2  in.  by 
^  in.  deep  and  tapped  internally  with  any 


SPRAY   CARBURETTOE  FOR   3^-H.P.   MOTOR, 


-2- *t 

Fig-.  90. — Sectional  View  of  Carburettor. 


100 


MOTOR    BICYCLE    BUILDING. 


convenient  fine  thread  for  screwing  to  the  main 
body  piece.  Or,  instead,  the  two  parts  can  be 
connected  by  a  plain  push-on  fit,  and  secured  by 


Fig.  91.— Cover  Piece  of  Carburettor. 

putting  three  or   four  small  screws  through  the 
flange  of  the  top  piece  into  the  main  body  piece. 


Fig.  92.— Base  Piece  of  Carburettor. 

This   method   will   answer   very    well   if   screwing 
is  inconvenient,  but  it  must  be  a  good  tight  fit. 
The  main  body  piece  is  now  chucked  by  the  top 


SPRAY   CARBURETTOR  FOR   3|-H.P.   MOTOR.     101 

end,  and  the  bottom  edge  faced  off  and  recessed 
out  Ij  in.  diameter  by  g  in.  deep,  to  receive  the 
bottom  or  base  piece.  The  casting  is  then  reversed 
in  the  chuck,  and  the  top  edge  faced  and  the  out- 
side turned  to  fit  the  top  piece  and  screwed  if 
necessary.  The  internal  flange  c  is  bored  out 
lT?g  in.  diameter  and  faced  on  the  top  side  only. 
The  extra  air  holes  should  now  be  drilled  in 
the  side  of  the  body  piece.  These  are  five  -^  -in. 
holes  spaced  equally  distant  on  a  f-in-  circle,  the 


Fig.  93. — Pattern  for  Gauge  Cone-piece. 

centre  being  drilled  and  tapped  to  receive  a  small 
cheesehead  screw  by  which  the  cover  piece  (Fig. 
91)  is  held  in  position.  This  piece  requires  drill- 
ing the  same,  so  that  the  holes  in  the  body  can  be 
completely  covered  or  fully  open.  The  face  of  this 
extra  inlet  and  also  the  cover  piece  (Fig.  91)  must 
be  trued  up  so  that  one  fits  flat  against  the  other. 
The  base  piece  D  (Fig.  90),  and  shown  separ- 
ately by  Fig.  92,  is  now  drilled  in  the  centre 
i  in.  diameter,  or  to  suit  the  thread  of  the  small 
petrol  tap  to  be  fitted  here,  for  f  in.  up.  Then  a 
£-in.  hole  is  drilled  to  within  £  in.  of  the  top, 


102  MOTOR    BICYCLE    BUILDING. 


diameter  with  the  top  end  coned  out  as  shown 
to  take  the  bottom  end  of  the  needle  valve.  This 
piecQ  should  now  be  mounted  between  the  lathe 
centres  and  turned  all  over,  Ij  in.  diameter  by  a 
bare  i  in.  thick,  to  fit  tightly  the  recess  in  the  body 
pieces,  to  which  this  base  piece  is  finally  fixed 
by  riveting,  or  by  spinning  over  the  thin  edge 
of  the  bottom  of  the  body. 

The  bottom  piece  E  (Fig.  90)  is  turned  f  in. 
diameter  by  f  in.  long,  and  the  top  conical  part 
D  is  turned  f  in.  long  by  f  in.  at  the  base,  taper- 
ing to  -3\  in.  at  the  top.  The  air  holes  F  (Figs. 
90  and  92)  are  six  in  number,  ^  in.  in  diameter, 
equally  spaced  on  a  l|-in.  circle.  The  gauze  cone 
piece  B  (Fig.  90)  should  now  be  cut  out,  bent 


Fig.  94.—  Bridge  Piece  of  Carburettor. 

to  shape,  and  soldered  at  the  joint  and  to  the  base 
piece  D  at  the  top  and  all  round  at  the  bottom,  so 
that  the  petrol  issuing  from  the  top  of  the  small 
hole  flows  over  the  copper  gauze  cone.  Fig.  93 
shows  the  size  and  shape  for  cutting  out  this 
piece. 

The  bridge  piece  G  (Fig.  90,  see  also  Fig.  94) 
should  now  be  drilled  J  in.,  and  the  shoulders 
turned  true  with  the  hole.  .  The  piece  is  then 
soldered  in  position  as  shown. 

The  valve  piece  H  (Fig.  90)  is  now  drilled  |  in. 
tapping  size,  and  turned  up  true  with  the  hole, 
If  in.  diameter  by  -^  in.  thick  at  the  centre  part, 
tapering  to  a  bare  ^  in.  at  the  edges  ;  the  boss  on 
the  top  is  YV  in-  in  diameter  by  ^V  in-  l°ng-  It 
should  be  tapped  and  screwed  to  the  needle  valve 
A,  which  is  a  piece  of  |-in.  steel  wire,  straight  and 
true. 


SPRAY   CARBURETTOR   FOR   3|-H.P.   MOTOR.     103 

After  the  valve  piece  H  is  screwed  to  the  needle- 
valve  piece  and  locked  by  a  small  lock  nut  (not 
shown),  it  should  be  mounted  between  the  lathe 
centres  and  the  brass  piece  H  skimmed  up  true. 
The  point  can  be  turned  quite  at  the  last,  before 
parting  off  the  centre  on  which  it  was  turned. 
The  brass  piece  H  is  fixed  in  such  a  position  on 
the  needle  valve  that  the  point  shuts  dead  on  the 
hole  at  the  same  time  as  the  under  edge  of  the 
piece  H  just  touches  the  flange  of  the  body  piece. 
These  two  joints  may  finally  be  ground  in  with 
just  a  touch  of  powdered  pumice  powder  and 
oil,  or  crocus  powder. 

A  loose  distance  piece  is  slipped  on  the  stem  of 
the  needle  valve  just  above  the  boss  of  H,  to  pre- 
vent the  valve  opening  more  than  £  in.,  and  a 
light  helical  spring  is  made  to  fit  over  the  boss  of 
H  and  bear  against  the  under  side  of  the  bridge 
piece  G.  This  spring  must  be  light,  and  rather 
weaker  than  the  inlet-valve  spring  of  the  motor. 

The  throttle  valve  is  a  disc  of  brass  about 
No.  18  gauge  riveted  or  screwed  to  the  casting  j, 
which  is  Ts^  in.  in  diameter,  with  half  filed  away 
where  the  disc  fits.  The  operating  level  is  one 
with  the  piece  to  which  the  disc  is  fastened. 

The  petrol  regulating  tap  to  screw  into  the 
bottom  of  E  can  be  purchased  for  9d.  to  Is.,  and 
should  be  of  about  2j  mm.  bore. 

The  outside  of  the  body  can  be  polished  and 
plated  to  give  a  good  finish. 


10* 


CHAPTER    VI. 

IGNITION    COILS    FOK    MOTOR    CYCLES. 

WHEN  petrol  is  vaporised,  and  its  vapour  com- 
bined with  air,  it  forms  an  explosive  mixture 
which  may  be  used  as  a  propulsive  force  in  driv- 
ing a  motor.  It  is  thus  utilised  in  specially  con- 
structed engines,  resembling  gas  engines,  the 
construction  of  which  has  been  fully  described  in 
the  previous  chapters.  The  explosive  mixture  of 
petrol  vapour  and  air  is  admitted  into  the  cylinder 
of  the  motor,  and  exploded  there  by  means  of 
electric  sparks  from  an  inductor  coil  specially 
constructed  for  the  purpose,  and  called  an  ig- 
nition coil.  This  is  worked  with  electric  current 
obtained  from  a  primary  battery,  or  from  a  4-volt 
accumulator,  the  latter  being  preferred  because 
of  its  superior  constancy  to  that  of  a  primary 
battery. 

Ignition  coils  for  petrol  motors  may  be  made  in 
one  or  two  types  :  (1)  a  plain  primary  coil  with  a 
wipe  arrangement  to  cause  the  spark,  and  (2)  a 
compound  primary  and  secondary  coil  with  a 
trembler  break  and  a  wipe  arrangement  combined 
to  produce  the  spark. 

To  make  a  plain  or  primary  coil,  first  procure 
enough  No.  22  gauge  iron  wire  to  form  a  bundle 
12  in.  -long  and  f  in.  in  diameter,  for  the  core  of 
the  coil.  Cut  a  number  of  12-in.  lengths,  and  pack 
as  many  as  possible  into  two  |-in.  curtain  rings. 
Then  carefully  push  some  lengths  down  the  centre 
of  the  bundle  until  it  fits  the  rings  tightly.  Next 
bind  the  bundle  tight  with  soft  iron  wire,  put  in 
a  dying  forge  or  kitchen  fire,  heat  to  a  red  heat, 
and  allow  to  cool  down  as  the  fire  dies  out  during 


IGNITION    COILS    FOR    MOTOR    CYCLES.      105 

a  period  of  several  hours.  This  anneals  the  iron 
and  makes  it  quite  soft,  a  necessary  property  in 
the  core  of  a  coil  to  ensure  rapid  magnetisation 
and  de-magnetisation. 

If  hard  iron  is  employed  in  making  a  core, 
more  electricity  is  required  to  magnetise  the  iron, 
and  it  retains  the  magnetism  after  the  electric 
current  is  shut  off,  whilst  a  similar  result  follows 
the  use  of  a  solid  core. 

The  annealed  bundle  of  wire  should  now  be 
made  warm  and  basted  with  hot  molten  paraffin 
wax  until  fully  saturated,  then  set  aside  to  cool. 
Take  off  the  rings,  and  unwind  the  binding  wire  ; 
at  the  same  time  wind  on  tightly  one  layer  of 
paraffined  tape.  Then  roll  one  turn  of  soft  brown 
paper  round  the  core  and  paste  the  edges.  Paste 
the  paper  and  roll  on  other  turns  until  a  tube  of 
pasted  brown  paper  is  formed  on  the  core  to  a 
thickness  of  ^  in. 

Whilst  this  is  drying  and  getting  firm,  prepare 
two  heads  for  the  coil,  or,  regarding  the  core  as 
the  body  of  a  bobbin  on  which  the  coil  of  wire  is 
to  be  wound,  prepare  two  heads  for  the  bobbin. 
These  heads  may  be  made  of  mahogany,  walnut, 
or  other  hardwood,  or  of  ebonite.  If  made  of 
wood,  they  should  be  soaked  in  melted  paraffin 
to  fill  the  pores.  In  shape  they  may  be  round, 
square,  or  octagonal,  and  if  of  wood,  they  should 
be  1  in.  thick  and  4  in.  in  diameter.  If  made  of 
ebonite  they  may  be  a  little  thinner.  Holes  must 
be  bored  in  the  centre  of  these  heads  to  exactly 
fit  the  ends  of  the  core,  and  secured  with  good 
glue. 

On  this  bobbin  wind  4  lb.  of  No.  18  soft  copper 
wire,  double  cotton  covered  and  paraffined.  First 
drill  a  small  hole  throjigh  one  of  the  heads,  close 
to  the  core,  and  push  8  in.  of  the  wire  through 
this  hole.  Then  twist  it  round  a  pencil  to  form  a 
spiral  or  helix.  This  end  will  be  used  for  connect-, 
ing  the  coil  to  other  parts  of  the  igniting  appa- 


106  MOTOR    BICYCLE    BUILDING. 

ratus.  Wind  on  one  layer  evenly,  then  tie  the 
last  turn  down  with  soft  cotton,  and  well  baste 
the  turns  of  wire  with  melted  paraffin.  Proceed 
with  the  rest  of  the  wire  in  the  same  manner, 
basting  each  layer  as  it  is  wound  on.  Finish 
winding  at  the  opposite  end  to  that  of  the  com- 
mencement, taking  the  wire  through  a  hole  near 
the  top  of  the  head,  and  forming  it  into  a  helix. 
Baste  the  whole  coil  well  with  hot  paraffin,  and 
roll  several  folds  of  paraffined  paper  round  the 
wire,  smoothing  down  each  fold  with  a  hot  iron. 
Then  fit  over  the  whole  a  cover  of  thin  sheet 
ebonite,  securing  with  a  lacing  of  silk  cord. 

It  is  usual  to  mount  a  brass  terminal  or  bind- 
ing screw  on  each  head,  and  to  solder  the  ends  of 
the  coil  to  these  terminals.  They  may  be  ob- 
tained from  dealers  in  electrical  sundries.  Now 
make  a  groove  in  the  surface  of  the  head  holding 
the  commencing  end  of  the  wire,  straighten  the 
wire,  and  force  it  in  this  groove.  Then  lay  bare 
the  part  to  go  under  the  base  of  the  terminal, 
form  it  into  a  loop,  fitting  the  tang  of  the  pillar, 
and  screw  this  down  tight.  The  finishing  end  of 
the  coil  should  be  fixed  to  the  other  terminal  in 
the  same  manner,  and  the  grooves  filled  in  with 
wax  coloured  to  match  the  wood.  If  the  coil  is 
put  in  a  protecting  case,  the  terminals  may  be 
attached  to  the  case,  and  then  the  helixes  of  wire 
will  be  useful  in  making  the  connections  between 
the  coil  and  the  terminals. 

Now,  with  two  lengths  of  No.  18  wire,  connect 
the  coil  to  the  two  terminals  of  a  4-volt  accumu- 
lator for  a  moment,  when  its  core  and  coils  will 
be  charged  with  electricity.  Then  disconnect  the 
coil  suddenly,  and  note  that  this  charge  leaps 
across  the  air  space  between  the  end  of  the  con- 
necting wire  and  terminal  (at  the  moment  of 
disconnecting  the  coil  from  the  accumulator)  in 
the  form  of  a  bright  spark  or  flash  of  light.  It  is 
this  spark  that  fires  or  ignites  the  explosive  mix- 


IGNITION    COILS    FOK    MOTOK    CYCLES.      107 

ture  in  a  petrol  motor,  and  the  maker  must 
arrange  the  make-and-break  mechanism  so  as  to 
break  or  disconnect  the  circuit  in  the  combustion 
chamber  at  the  moment  of  breaking  contact,  and 
therefore  differs  from  the  action  of  the  trembler 
coil. 

To  make  a  compound  primary  and  secondary 
coil  with  trembler  break,  proceed  as  for  a  plain 
primary  coil,  preparing  the  coil  in  the  same 
manner,  but  this  need  only  be  7  in.  long.  Bind 
the  bundle  of  wires  with  one  layer  of  paraffined 
tape  as  the  rings  and  binding  wire  are  being 
removed.  Then  warm  a  sheet  of  thin  ebonite  -^ 
in.  thick  and  7  in.  wide,  roll  it  round  the  core 
firmly  to  form  two  folds,  and  fix  the  edge  with 
Prout's  elastic  glue  melted  with  a  hot  iron.  This 
will  form  the  bobbin  body  of  the  coil,  to  which 
must  now  be  fitted  two  ebonite  discs  S^in.  in 
diameter  and  f  in.  thick,  securing  them  to  the 
body  with  good  shellac  varnish. 

The  holes  in  the  discs  should  be  turned  true 
and  made  to  fit  the  ebonite  sleeve  on  the  core, 
so  as  to  require  very  little  varnish  to  hold  them 
on.  Also,  one  of  the  heads  or  discs  must  be 
pressed  on  over  the  core,  so  as  to  allow  f-in.  of 
the  bare  wire  to  protrude  beyond  the  head  to  serve 
as  an  electro-magnet  for  the  trembler  arrange- 
ment. These  ends  should  be  free  from  tape  and 
ebonite,  and  made  level  with  a  file. 

When  the  bobbin,  thus  prepared,  has  set  hard 
and  firm,  wind  it  first  with  the  primary  coil. 
Meanwhile  prepare  some  sheets  of  paraffined 
paper  in  the  following  manner :  Procure  about 
eighteen  sheets  of  good  white  demy  paper  free 
from  specks  and  holes,  each  22  in.  by  18  in., 
examine  each  sheet  by  holding  it  up  to  the  light 
and  reject  the  faulty  parts.  Cut  from  these  sheets 
of  paper  forty  strips,  each  9  in.  by  6  in.,  to  serve 
as  insulators  between  the  layers  of  wire,  and  sixty 
squares,  each  6  in.  by  5  in.,  for  the  condenser. 


108  MOTOR    BICYCLE    BUILDING. 

Next  procure  about  2lb.  of  best  solid  paraffin 
(paraffin  wax),  cut  it  into  -shreds,  and  melt  it  in 
a  square  shallow  tin  baking  dish,  placed  in  a  stew 
pan  containing  water,  kept  hot  over  a  fire.  The 
sheets  of  paper  are  to  be  passed  through  the 
melted  liquid  paraffin  with  the  aid  of  a  pair  of 
wooden  tongs,  scraped  over  the  edge  of  the  dish 
to  free  them  from  surplus  wax,  and  hung  on  lines 
near  the  fire  to  drain  and  dry.  They  are  best 
hung  by  small  wire  clips  attached  to  one  corner 
of  each  sheet,  and  when  cold,  are  ready  for  use. 

The  primary  coil  must  be  formed  of  soft  No.  18 
copper  wire,  double  cotton  covered,  and  previ- 
ously soaked  in  the  melted  paraffin  ;  a  little  over 
£lb.  of  "wire  will  be  required.  First  make  a  small 
hole  through  the  ebonite  head  which  will  hold  the 
trembler,  close  to  the  core.  Pass  3  in.  of  the 
primary  wire  through  this  hole,  wrap  one  strip  of 
the  paraffined  paper  round  the  core,  carefully  wind 
on  one  layer  of  the  primary  wire  with  each  turn 
closely  sidfe  by  side,  and  secure  the  last  turn  with 
soft  cotton  to  hold  the  wire  firmly  whilst  being 
basted  with  hot  paraffin.  Then  wrap  another 
strip  of  paraffined  paper  round  the  first  layer  and 
wind  on  the  next  layer  of  wire,  bringing  the  finish- 
ing end  through  another  small  hole  in  the  same 
head,  but  on  the  opposite  side  to  the  first.  Then 
secure  the  last  turn  with  soft  cotton.  One  of 
these  ends  of  the  primary  wire  will  be  connected 
to  one  foot  of  the  trembler  bridge,  and  the  other 
to  a  terminal  fixed  in  the»ebonite  head. 

Attention  must  now  be  paid  to  the  shell  of 
ebonite  between  the  primary  and  the  secondary 
coil.  This  is  of  great  importance,  as  the  length 
and  density  of  the  spark  from  this  coil  depends 
greatly  on  the  perfection  of  insulation  between 
the  primary  and  secondary  coils. 

Some  coil  builders  adopt  an  almost  perfect 
method  of  insulation  by  having  an  ebonite  tube 
to  form  the  shell.  This  may  be  done  in  the  follow- 


IGNITION    COILS    FOR    MOTOR    CYCLES.      109 

ing  manner :  Two  small  discs  of  ebonite  are  first 
fitted  on  the  core  to  serve  as  bobbin  ends  to  the 
primary.  Then  the  larger  heads  for  the  coil  are 
made  to  go  over  these,  and  fit  an  ebonite  tube 
slid  over  the  primary  wire.  This  method  requires 
a  lathe  to  turn  the  parts,  and  also  careful  fitting. 
The  next  best  method  with  the  coil  under  con- 
sideration is  to  get  sheet  ebonite  ^  in.  thick,  wide 
enough  to  just  fit  in  between  the  bobbin  heads, 
and  long  enough  to  form  seven  folds  around  the 
primary.  Soften  this  in  boiling  water,  and  roll 
it  whilst  hot  round  a  wooden  roller  slightly 
smaller  than  the  primary  coil.  Then  wind  on 
enough  tape  to  keep  it  in  shape  until  cold.  When 
cold,  remove  the  tube  and  work  its  outside  edge 
over  the  coil.  Then  stick  the  outside  edge  down 
with  thick  shellac  varnish.  Whilst  the  varnish 
is  wet,  wind  on  one  layer  of  tape  very  tight,  to 
bring  the  ebonite  sheet  in  close  contact  with  the 
primary  wire,  and  allow  it  to  remain  until  the 
varnish  has  set  hard. 

The  secondary  coil  is  formed  of  silk-covered 
No.  36  copper  wire,  which  must  be  free  from  kinks 
and  knots.  If  any  of  these  faults  are  detected 
whilst  winding,  they  must  be  cut  out,  the  ends  of 
the  wire  bared  of  its  silk  covering,  'the  ends 
twisted  together,  rubbed  with  resin,  and  then 
soldered,  after  which  they  must  be  again  covered 
with  silk.  Soldering  fluid  -must  not  be  used  in 
soldering  any  part  of  a  coil. 

The  quantity  of  wire  required  will  be  in  pro- 
portion to  the  length  of  spark  desired  from  the 
coil.  Half-a-pound  of  No.  36  wire  should  yield  a 
i-in.  spark,  fib.  a  f-in.  spark,  and  1  Ib.  a  1-in. 
spark  in  air,  when  wound  over  the  primary  previ- 
ously described.  The  shorter  spark  will  probably 
be  sufficient  to  ignite  the  charge  in  a  3^-h.p. 
petrol  motor. 

The  bobbin  with  the  primary  coil  must  first  be 
mounted  on  a  suitable  winder.  Then  one  of  the 


110  MOTOR    BICYCLE    BUILDING. 

strips  of  paraffined  paper  must  be  rolled  round 
the  ebonite  tube  and  smoothed  down  with  a  hot 
iron.  Next  bore  a  small  hole  obliquely  through 
the  edge  of  the  left-hand  head,  and  let  it  come 
out  close  to'  the  primary.  Thrust  a  few  inches  of 
No.  24  copper  wire  down  this  hole,  bend  up  the 
inner  end  to  form  a  hook,  and1  tie  this  firmly  with 
soft  cotton.  Then  solder  the  commencing  end  of 
the  secondary  wire  to  the  hook  thus  formed,  and 
make  the  top  portion  into  a  helix  for  connecting 
the  inner  part  of  the  coil  to  a  terminal.  The  bob- 
bin of  No.  36  wire  should  run  freely  on  stout  wire, 
and  be  wound  over  the  primary  in  the  same  direc- 
tion as  this  is  wound  over  the  core.  Each  turn 
must  be  wound  on  evenly  side  by  side,  and  when 
the  first  layer  has  been  wound,  it  must  be  covered 
with  one  and  a  half  turns  of  paraffined  paper 
smoothed  down  as  before.  Then  wind  on  another 
layer  in  the  same  careful  manner ;  but  let  it  finish 
with  two  turns  of  the  head  of  the  coil.  Proceed 
thus  with  each  layer,  winding  and  insulating  as 
at  first,  and  bringing  each  a  little  short  of  the 
heads,  to  prevent  accidental  sparking  at  these 
points,  with  consequent  ruin  of  the  coil.  The 
vacant  spaces  may  be  filled  with  soft  cotton 
before  putting  on  the  next  layer  of  paraffined 
paper. 

The  winding  must  stop  when  the  last  layer  has 
reached  the-  head  opposite  to  that  holding  the 
commencing  wire,  and  the  end  of  this  layer  must 
be  tied  with  soft  cotton ;  about  6  in.  should  be 
left  free  to  form  a  helix  for  connecting  to  a  ter- 
minal. 

The  whole  should  now  be  covered  with  par- 
affined paper,  then  with  wide  silk  ribbon  wound 
on  tightly,  stitched  down,  and  then  the  whole  coil 
soaked  in  melted  paraffin  until  it  ceases  to  give 
out  bubbles,  when  it  may  be  taken  out  to  drain 
and  cool. 

A  condenser   must   next   be   prepared   to   take 


IGNITION    COILS    FOR    MOTOR    CYCLES.      Ill 

up  the  extra  induced  charge  of  electricity  and 
give  it  to  the  secondary  and  sparking  circuit, 
thus  increasing  the  density  of  the  sparks.  This 
condenser  is  formed  of  fifty  sheets  of  good  tinfoil, 
each  65  in.  by  4  in.,  alternating  with  the  sheets 
of  paraffined  paper  already  prepared.  First  lay 
one  of  these  sheets  on  a  smooth  board,  and  drive 
four  wire  nails  in  at  the  corners  to  form  a  guide 
for  laying  the  tinfoil.  Lay  the  first  sheet  of  tin- 
foil with  the  left-hand  end  protruding  1  in. 
over  the  paper,  and  the  sides  J  in.  in  from 
the  sides  of  the  paper.  Then  lay  another  sheet 
of  paper  evenly  with  the  first,  and  on  it  lay 
another  sheet  of  tinfoil  with  the  right-hand  end 
projecting  1  in.  over  the  paper.  Thus  lay  each 
alternate  -sheet  of  paper  and  of  tinfoil  so  as  to 
have  each  alternate  sheet  of  tinfoil  overlapping 


Fig.  95. — Diagram  of  Condenser  Layers. 

the  paper  at  each  end  of  the  pile  as  shown  in 
Fig.  95,  where  the  dotted  lines  represent  the  paper 
and  the  thick  lines  the  tinfoil.  When  all  the 
sheets  have  thus  been  made  into  a  pile,  put  two 
or  three  more  sheets  of  paper  on  top,  then  a  piece 
of  blotting  paper,  and  on  this  a  heavy  iron  made 
warm  enough  to  soften  the  pile,  but  not  to  make 
the  paraffin  run.  When  cold,  roll  it  round  two 
binders  of  paraffined  silk  ribbon  to  firmly  bind 
the  bundle.  Next  get  two  6-in.  lengths  of  No.  22 
soft  clean  copper  wire  for  connecting  wires.  Fix 
one  of  these  to  each  end  of  the  pile  by  rolling  the 
projecting  tinfoils  around  the  wire,  then  stitching 
it  in  that  position  with  No.  36  soft  copper  wire 
threaded  through  a  darning  needle. 

The    trembler    arrangement    for    making    and 
breaking  the  primary  circuit  consists  of  an  electro- 


112 


MOTOR    BICYCLE    BUILDING. 


magnet  with  its  coils  connected  in  series  with 
the  battery  and  thus  forming  part  of  the  primary 
circuit.  This  electro-magnet  is  furnished  with 
an  armature  attached  to  a  spring  so  arranged  as 
to  form  a  loop  of  the  circuit,  capable  of  being 
broken  to  form  a  gap  when  the  current  is  switched 
on  to  the  coil.  It  is  this  breaking  action  of  the 
armature  that  gives  the  required  spark  from  the 
secondary  coil,  and,  as  this  causes  a  momentary 
cessation  of  current  in  the  electro-magnet,  it  loses 
its  hold  on  the  armature,  which  is  drawn  by  its 
spring  back  to  close  the  gap,  and  complete  the 
circuit  again.  This  action  of  breaking  and  clos- 
ing the  circuit  is  so  rapid  as  to  give  it  the 


Fig.  96. — Longitudinal  Sectional  Elevation  of  Trembler. 

appearance  of  trembling,  hence  the  name  of  trem- 
bler being  given  to  this  part.  The  electro-magnet, 
armature,  arid  other  parts,  may  be  constructed 
to  form  a  separate  instrument,  and  may  be  placed 
in  any  part  of  the  primary  circuit.  But  it  is 
usual  for  compactness  to  construct  it  on  one 
head  of  the  coil  itself,  the  core  of  the  coil  serving 
as  the  electro-magnet,  arrangements  for  this  hav- 
ing been  made  when  forming  the  core  and  bobbin 
of  the  coil. 

The  armature  of  the  trembler  A  (Figs.  96  to 
99)  is  a  piece  of  iron  bar  f  in.  in  diameter  and 
5  in.  thick.  This  is  attached  to  one  end  of  a  strip 
of  hard  German  silver  f  in.  wide,  ^  in.  thick, 
and  2  in.  long,  by  two  short  brass  screws  or  rivets. 


IGNITION    COILS    FOR    MOTOR    CYCLES.     113 


The  other  end  of  the  strip  B  is  pierced  with  a 
small  square  hole  to  fit  over  the  top  of  a  support- 
ing pillar  c,  as  shown  in  Fig.  97.  When  the 
armature  spring  is  fixed  to  this  pillar  with  a  set 
screw,  the  armature  must  be  exactly  over  the 


Fig.  97. — Transverse  Sectional  Elevation  of  Trembler. 

centre  of  the  core,  with  the  two  iron  faces  T^  in. 
apart  (see  Figs.  96  and  97).  In  this  position  it 
is  spanned  by  a  bridge  D,  made  with  a  strip  of 
brass  bent  as  shown  in  Fig.  96,  with  feet  pierced 
with  holes  for  fixing  to  the  head  of  the  coil,  and 
a  screwed  hole  in  the  centre  over  the  armature  to 
hold  the  contact  screw.  The  trembler  make-and- 
break  will  take  place  between  the  tip  of  this 
screw  and  the  armature  spring,  and  as  sparks  will 
occur  when  the  circuit  is  broken,  and  these  sparks 
will  burn  brass  rapidly,  the  points  of  contact 


D 


Fig-  98.— Plan  of  Armature  and  Spring. 

must  be  protected  with  platinum.  These  points 
are  best  made  with  platinum  wire  No.  16  gauge. 
Drill  a  small  hole  3  in.  up  the  tip  of  the  contact 
screw,  fit  the  platinum  wire  into  this  hole,  cut  it 
off,  leaving  ^V  ^n-  projecting,  and  splay  this  over 


114  .MOTOR    BICYCLE    BUILDING. 

the  tip  to  form  a  rivet  head  E.  Treat  the  lower 
contact  piece  in  a  similar  manner.  As  the  cur- 
rent to  work  the  coil  will  pass  this  spot,  and  as 
the  density  of  the  sparks  will  be  proportioned  to 
the  density  of  the  current  passing  here,  these 
contact  points  must  fit  each  other  with  level 
surfaces,  so  as  to  offer  small  resistance  to  the 
current.  One  end  of  the  primary  coil  will  be 
clipped  under  one  of  the  feet  of  the  break  bridge, 
and  the  other  end  to  a  separate  terminal  on  the 


Fig.  99.— Plan  of  Trembler  on  End  of  Coil. 

outer  edge  of  the  head  as  shown  at  1  (Fig.  99). 
This  terminal  will  be  connected  to  the  battery, 
and  the  other  line  from  the  battery  will  be  con- 
nected to  the  break  pillar. 

The  vibrations  of  the  armature,  and  also  the 
character  of  the  sparks,  will  be  regulated  by  the 
adjustment  of  the  contact  screw,  which  must 
be  fitted  with  a  lock  nut,  as  shown,  to  rigidly 
secure  such  adjustments. 

AH  the  parts  of  the  coil  and  condenser  having 
been  prepared,  they  must  now  be  put  together. 


IGNITION    COILS    FOR    MOTOR    CYCLES.      115 


The  best  made  coils  are  all  fitted  with  ebonite 
cases  or  cylinders,  secured  at  the  ends  with  ebonite 
covers  made  to  screw  on  the  ends  and  furnished 
with  connecting  terminals  on  the  outside.  In 
home-made  coils  a  case  can  be  made  of  hardwood 
well  soaked  in  melted  paraffin.  If  a  rectangular 
case  is  prepared,  the  condenser  may  be  first  fixed 
in  the  bottom  of  the  case,  after  having  enclosed 
the  connecting  wires  in  india-rubber  tubing,  and 
brought  the  ends  of  both  near  the  trembler  end 
of  the  coil.  The  coil  must  then  be  fitted  close 
to  the  condenser,  and  connected  to  it  as  shown  in 
Fig.  100  ;  that  is,  one  wire  from  the  condenser  to 
the  foot  of  the  bridge,  and  the  other  to  the  foot 


Fig.  100.— Diagram  of  Coil  Connections. 

of  the  break  pillar  c.  Terminals  may  be  fixed 
to  the  outside  of  the  case,  and  short  pieces  of 
flexible  cord  made  to  connect  these  with  the  inside 
terminals. 

If  the  coil  is  to  be  fitted  into  an  octagonal 
wooden  case,  or  into  a  cylindrical  case  of  ebonite, 
it  should  be  first  enveloped  in  several  turns  of 
sheet  ebonite  to  make  sure  of  insulation  between 
the  secondary  and  condenser.  xhen  the  con- 
denser should  be  warmed  over  a  bottle  of  hot 
water  and  curved  to  its  shape,  and  fitted  to  one 
side  of  the  coil  and  bound  with  silk  ribbon  before 
being  fitted  in  the  case.  In  some  1-in.  spark 
coils,  insulation  is  made  doubly  sure  by  placing 
the  coil  and  condenser  into  the  case  with  the 


116  MOTOR    BICYCLE    BUILDING. 

trembler  part  uppermost,  and  then  filling  up  all 
spaces  with  melted  paraffin. 

When  fitting  the  coil  to  its  case,  and  this  to 
the  motor,  pay  special  attention  to  the  insulation 
of  all  connecting  wires.  They  are  best  insulated 
when  sheathed  with  rubber  tubing.  The  terminals 
from  the  secondary  coil  must  be  kept  at  a  distance 
from  each  other,  and  from  other  terminals  or 
metal  work,  and  their  tangs  must  not  be  near 
the  wire  anywhere.  The  leading  wires  should  not 
touch  each  other,  or  cross  one  another  closely,  nor 
rest  against  the  coil  or  the  condenser.  Neglect 
of  these  precautions  may  cause  leakage,  arid 
consequent  failure  in  getting  good  sparks. 

Fig.  101  is  a  diagram  showing  the  method  of 
working  and  the  action  of  these  two  coils,  A  and 
B  representing  the  cylinders  of  two  motors.  In  A 
there  is  an  ordinary  sparking  plug  c  attached 
to  the  secondary  of  a  compound  trembler  coil  D1, 
the  primary  of  which  is  in  connection  with  a 
battery  when  the  cam  E  closes  the  primary  circuit 
by  pressing  together  the  two  springs  at  F.  Whilst 
they  are  thus  pressed  together  the  coil  is  excited, 
and  a  stream  of  sparks  flow  across  the  gap  in  the 
sparking  plug,  igniting  the  charge  in  the  cylinder. 
In  B  there  is  a  wipe  plug  G,  consisting  of  a 
platinum-tipped  rod  and  a  platinum-faced  spring. 
The  rod  works  in  an  insulated  stuffing-box,  and 
its  platinum  tip  is  in  contact  with  the  spring 
(connected  to  the  cylinder)  when  the  cam  H  presses 
it  into  the  cylinder.  When  the  cam  passes  the  tip 
of  this  rod,  a  helical  spring  J  pulls  it  sharply 
away  from  the  spring  G,  and,  as  the  previous 
contact  of  these  parts  closed  the  circuit  of  the 
battery  through  the  plain  coil  D2,  so  this  pulling- 
away  action  breaks  contact  and  a  flashing  spark 
passes  between  the  two  separated  parts  at  G.  It 
must  be  noted  that  this  spark  only  flashes  across 
the  gap  between  the  separated  parts  at  the  mo- 
ment of  separation,  or,  in  other  words,  "  at  the 


IGNITION    COILS    FOR    MOTOR    CYCLES.      117 

break,"  but  not  the  "  make  "  of  the  circuit.  This 
must  be  taken  into  consideration  when  arranging 
the  timing  of  the  ignition,  by  adjusting  the  wip- 
ing cam.  In  A  the  sparking  begins  when  the  two 
springs  at  F  are  brought  into  contact,  and  con- 
tinues whilst  they  are  in  contact;  but  in  B  there 
is  only  one  flash  when  contact  is  broken.  Sure 
ignition  is  ensured  by  the  use  of  a  compound  coil 
with  trembler  attachment,  but  the  timing  of  the 


Fig.  101. — Diagram  Showing  Working  of  Ignition  Coils. 

ignition  is   said  to  be  most  correct  with   a  plain 
coil. 

In  Fig.  101  the  exact  form  of  the  parts,  and 
position  of  the  cams,  has  not  been  attempted,  as 
the  principal  of  the  action  only  has  been  illus- 
trated. However  the  cams  may  be  formed  or 
fixed,  they  should  be  made  so  as  to  be  easily  and 
quickly  adjusted. 


118 


CHAPTER     VII. 

LIGHT-WEIGHT     PETROL     MOTOR     FOR     ATTACHMENT     TO 
ROADSTER    BICYCLE. 

THE  petrol  motor  to  be  described  in  this  chapter 
weighs,  with  a  14-lb.  flywheel,  about  25  lb.,  which 
may  be  reduced  by  using  a  lighter  flywheel.  Thus 


Fig.  102.— lection  o"  Light-weight  Motor  Crank  Case. 

it  will  be  specially  adapted  for  fitting  on  to  an 
ordinary  roadster  bicycle,  whose  front  forks 
have  been  strengthened  with  tubular  stays.  Al- 
though the  motor  is  light  and  simple  in  con- 
struction, nothing  has  been  sacrificed  to  effici- 


MOTOK  FOR   ATTACHMENT   TO   BICYCLE.      119 

oncy,  strength,  or  bearing  surface.  It  will 
develop  li  h.p.,  or,  if  very  well  made,  should 
approach  If  h.p.  The  position  for  the  engine 
is  well  up  on  the  bottom  tube,  in  a  vertical  posi- 
tion, thus  enabling  a  long  belt  to  be  used,  so  as 
to  grip  the  motor  pulley.  The  main  shaft  bear- 
ing is  3  ^  in.  long  by  £  in.  diameter,  giving  long 
life  and  steadiness  in  running.  To  complete  the 


Fig.  103.— Plan  of  Light- weight  Motor  Crank  Case. 

engine  from  the  rough  castings  a  screw-cutting 
lathe  of  4i-in.  or  5-in.  centre  is  essential,  in 
addition  to  the  ordinary  small  tools  of  an  en- 
gineer's workshop. 

Specification. — One  and  a  half  h.p.  air-cooled 
vertical  engine.  The  lug  which  fastens  it  to  the 
frame  may  be  suitably  fitted  on  the  pattern  for 
those  who  prefer  an  inclined  position  for  the 


120  MOTOR    BICYCLE    BUILDING. 

engine.  Cylinder  2j-in.  bore  by  2i-in.  stroke; 
outside  flywheel,  aluminium  crank  case ;  high  ten- 
sion electric  ignition ;  spray  carburettor  of  simple 
design ;  V-belt  drive  on  the  back  wheel. 

Crank  Case. — The  pattern  for  the  crank  case 
(Figs.  102  and  103)  should  be  made  with  due 
allowance  for  shrinkage  and  machining.  A  core- 
box  of  rather  a  complicated  pattern  will  be  re- 
quired to  core  the  large  interior,  with  depressions 
in  the  back  of  the  case  as  shown  for  the  two-to- 
one  gear,  for  the  hole  through  for  the  main 
bearing  bush,-  and  for  the  upper  opening  con- 
necting the  cylinder.  The  pattern  may  be  made 
to  leave  its  own  core  in  the  back  of  the  case  for 
the  exhaust  valve  cam  chamber.  To  machine  the 
crank  case,  hold  it  by  the  main  bearing  extension 
in  a  three-  or  four-jaw  chuck,  and  bore  out  the 
main  bearing  hole  and  the  depression  for  the 
small  gear  wheel  to  the  dimensions  given  in 
Fig.  102.  Face  the  edge  of  the  case,  and  true 
up  its  inside  edge  i  in.  deep.  If  a  suitable  chuck 
is  not  available,  the  hole  may  be  drilled  halfway 
from  each  side,  and  the  operations  of  truing  up 
tne  face  and  inside  edge  and  recessing  may  be 
done  on  a  mandrel  between  the  lathe  centres  : 
but  this  will  not  make  such  a  true  job  of  it  as  if 
all  the  operations  were  done  at  one  chucking. 
The  hole  for  the  main  shaft  bushing  is  1  in.  in 
diameter.  The  recess  for  the  16-tooth  pinion  is 
£  in.  deep  and  \\  in.  in  diameter.  The  inside 
back  of  the  case  will  not  require  machining,  ex- 
cept at  the  two  recessed  parts  for  the  16-tooth 
pinion  and  the  32-tooth  wheel.  The  1-in.  hole 
must  be  quite  parallel,  and  if  a  1-in.  reamer  is 
available,  bore  the  hole  J-  in.  under  size  and 
reamer  out  by  hand  in  the  vice. 

Hole  for  Cam  iShaft  Bushing. — Next  bore  out 
the  hole  for  the  exhaust  cam  shaft  bushing  and 
the  recess  for  the  32-tooth  wheel ;  this  should  be 
ij-  in.  in  diameter  and  the  recess  i  in.  deep  by 


MOTOR   FOR  ATTACHMENT   TO   BICYCLE.     121 

2^  in.  in  diameter.  If  the  chuck  is  large  enough, 
the  casting  may  be  set  over  till  the  hole  runs 
true  to  perform  this  operation.  If  not,  it  may  be 
done  on  an  angle-plate  bolted  to  the  face-plate, 
the  boring  of  this  hole  and  the  recessing  being 
left  until  the  top  flange  for  the  cylinder  has 
been  machined.  Whichever  way  it  is  done,  it 


Fig.  105. 
Figs.  104  and  105.— Crank  Case  Cover. 

must  first  be  marked  out  with  its  centre  lA  in. 
full  from  the  centre  of  the  main  shaft  hole.  To 
do  this,  plug  it  with  a  piece  of  hardwood,  mark 
off  the  Is  in.,  and  scribe  a  f-in.  circle  from  this 
centre,  and  put  centre-punch  dots  round  this 
circle  as  a  guide  for  setting  and  boring. 

Machining  Top  Flange,   etc. — To  machine  the 
top  flange,   fasten   the  casting  to  the  angle-plate 


122  MOTOR    BICYCLE    BUILDING. 

with  a  long  bolt  through  the  main-shaft  hole,  the 
trued-up  face  being  on  the  plate.  A  piece  of 
paper  should  be  placed  between  this  face  and  the 
angle-plate  to  avoid  getting  it  dented  or  bruised, 
as  this  face  and  the  trued-up  inside  edge  must  be 
kept  perfect  to  ensure  an  oil-tight  fit  for  the 
cover  (Figs.  104  and  105).  With  the  casting  true, 
true  up  the  face  of  the  flange  and  the  outside  edge 
to  3|  in.  in  diameter,  and  turn  out  the  recess 
for  the  cylinder  edge,  2J-~  in.  in  diameter  by  a 
bare  J  in.  deep.  Now  bolt  the  casting  to  the 
machine  up  the  back  of  the  case.  The  cam  shaft 
hole  must  be  £  in.  through,  and  the  face  for  the 
cover  (Figs.  106  and  107)  for  the  exhaust  cam 
chamber  is  T°7  in.  from  the  edge  of  the  cam-shaft 
bearing. 

Advance  Spark  Apparatus. — If  the  advance 
sparking  apparatus  is  to  be  purchased,  it  should 
be  bought  before  the  crank  case  is  machined, 
some  being  small  enough  to  work  in  the  space 
here  specified,  while  some  are  larger,  and  in  this 
case  a  small  recess  must  be  turned  in  the  top  of 
the  main  bearing  part.  The  cover  (Figs.  106  and 
107)  will  then  not  require  the  piece  cut  out  of 
bottom,  but  will  be  quite  circular.  At  this 
chucking,  the  face  of  the  main  shaft  bearing  may 
be  trued  up,  so  that  its  length  from  inside  the 
face  to  outside  is  3T\in. 

Assembling  the  Crank  Case. — The  clip  holding 
the  motor  to  the  frame  tube  may  next  be  bored 
to  suit  the  tube.  Roughly  file  up  the  faces  of 
the  two  parts  till  they  fit  squarely  together.  Then 
mark  off  and  drill  for  four  |-in.  or  -j^-in.  screws 
to  hold  the  parts  together,  the  holes  being  clear- 
ance in  the  bottom  half  and  tapping  in  the  top 
half.  Bolt  the  two  halves  together,  and  bore  them 
to  size,  either  on  the  angle-plate  in  the  lathe 
or  on  the  drilling  machine.  To  ensure  a  smooth, 
true  hole,  a  bit  or  a  reamer  should  be  put  through 
to  finish.  Remove  the  screws  and  file  ~Y  ^n-  °^ 


MOTOR   FOR  ATTACHMENT   TO   BICYCLE       123 

each  to  give  the  necessary  clearance  to  allow  the 
clip  to  grip  the  tube.  The  pins  may,  if  thought 
necessary,  be  long  enough  to  come  through  and 
take  a  locknut.  In  tapping  aluminium,  use 
paraffin  as  a  lubricant,  and  do  not  allow  much 
swarf  to  accumulate  in  the  flutes  of  the  tap,  or 
the  thread  will  tear  up.  Drill  and  tap  a  hole 
at  A  (Fig.  103)  to  suit  the  oiling  arrangement. 
For  injecting  oil  with  an  oil  can  a  J-in.  Whit- 
worth  thread,  with  a  plain  screwed  plug,  will 
do;  but  for  an  oil  pump  worked  from  the  saddle 
a  larger  hole,  to  suit  the  particular  connection 
used,  will  be  necessary.  Another  hole  must  be 
drilled  and  tapped  in  the  bottom  of  the  case 


Fig.  100.  Fig.  107. 

Figs.  100  and  107. — Giver  for  Exhaust  Cam  Chamber. 

for  letting  out  the  waste  oil,  and  this  may  be 
fitted  with  a  |-in.  screw  plug ;  but  a  small  waste- 
oil  tap  is  handier  and  gives  a  better  appearance. 
The  i-in.  Whitworth  hole  B  (Fig.  103),  to  receive 
the  exhaust-valve  lift-rod,  must  be  left  till  after 
the  cylinder  is  fitted. 

Crank-case  Cover. — The  crank-case  cover  may 
now  be  turned  and  fitted  to  the  case.  A  |-in.  lug 
is  left  on  the  back  by  which  to  chuck  it  and  to 
form  the  air  outlet.  Only  the  edge  and  the  part 
which  fits  in  and  against  the  case  will  require 
machining.  It  must  be  made  an  oil-tight  fit  by 
being  turned  nearly  to  size  and  being  then  ground 
in  with  powdered  pumice-stone.  It  should  be 
left  about  T^  in.  larger  in  diameter  than  the  case, 


124  MOTOR    BICYCLE    BUILDING. 

and  the  edge  should  be  milled  to  facilitate  hold- 
ing whilst  grinding-in  and  for  removal.  The 
cover  is  secured  to  the  case  by  four  £-in.  screws, 
as  shown  in  Fig.  104.  The  cover  must  be  chucked 
again,  back  outwards,  and  the  air-hole  in  the 
centre  formed.  A  flange  should  be  left  round 
this,  as  shown  in  Fig.  105,  so  that  the  oil  splashed 
over  the  cover  may  run  round  the  hole  and  down 
again  to  the  bottom  of  the  case,  instead  of  leak- 
ing out  on  the  outside.  The  hole  may  be  TT¥  in. 
or  larger,  and  the  head  of  the  flange  ^  in.  in 
diameter.  A  valve  may  be  made  of  this  if  thought 
desirable  by  fitting  a  yV^n>  cycle-ball,  but  it  is 
not  necessary  .unless  automatic  lubrication  is 
fitted. 

Small  Cover. — The  small  cover  (see  Figs.  106 
and  107)  may  be  bored,  turned  on  the  edge  to 
1|  in.,  and  faced  on  the  inside.  Bore  the  hole 
for  the  bush  i-i  in.,  and  just  true  up  the  project- 
ing edge.  The  piece  is  fastened  to  the  case  by 
three  £-in.  screws  with  countersunk  heads,  as 
these  must  not  project  beyond  the  face  of  the 
cover. 

Buahes. — The  main  bush  of  phosphor-bronze  is 
3~  in.  long  by  1  in.  in  diameter,  with  a  f-in.  hole. 
Chuck  the  casting,  bore  the  hole  ^  in.  under  size, 
and  finish  with  a  1-in.  reamer.  Knock  the  bush 
on  a  tree  mandrel,  and  turn  it  a  tight  fit  for  the 
case,  so  that  it  requires  driving  in  with  a  mallet. 
A  £-inch  peg  may  be  fitted  half  in  the  bush  and 
half  in  the  case,  f  in.  deep,  to  prevent  any  possi- 
bility of  the  bush  shifting.  When  the  bush  is 
fitted,  knock  it  on  the  mandrel  again,  and  face 
off  the  ends  flush.  Prepare  the  bushes  for  the 
exhaust  cam  shaft  in  the  same  manner.  The  one 
in  the  case  is  f  in.  long  by  -}i  in.  in  diameter,  with 
a  4-in.  hole.  The  cover  bush  is  ^-f  in.  by  J-'.  in., 
with  a  i-in.  hole.  Leave  these  holes  a  shade  under 
size,  knock  in  the  bushes,  screw  the  cover  in  place, 
and  pass  a  i-in.  reamer  through  both  whilst  in 


MOTOR   FOR  ATTACHMENT   TO   BICYCLE.      125 

position.  Be  sure  the  main  bush  hole  is  at  right 
angles  with  the  top  flange  face,  the  exhaust  cam 
shaft  hole  parallel  with  the  main  bush  hole,  and 


2O  THREADS 


Fig.  108. — Section  of  Li0ht- weight  Motor  Cylinder. 

the  hole  in  the  tube-clip  at  right  angles  with  the 
main  shaft  hole. 

Cylinder  Castings. — Dress  up  the  cylinder  cast- 
ings, taking  off  all  lumps  and  mould  marks, 
level  the  bottom  part  that  fits  on  the  crank  case 
square  with  the  sides,  and  mark  off.  Plug  a 


126  MOTOR    BICYCLE    BUILDING. 

piece  of  hardwood  across  the  mouth  of  cylinder, 
taking  care  not  to  drive  it  in  too  hard,  and  from' 
the  edges  of  the  cored  hole  find  the  centre.  From 
this  describe  with  the  dividers  a  circle  2.\  in.  full 
in  diameter,  and  centre-dot  lightly  with  about 
eight  dots  at  equal  distances  round  the  circle,  as 
a  guide  for  boring.  In  a  similar  manner  plug 
the  openings  in  the  top  of  the  cylinder  for  the 
inlet  valve  and  sparking  plug,  and  mark  off  the 
two  openings  so  that  their  centres  are  exactly 
2f^  in.  apart.  As  the  finished  sizes  are  1T"7.  in. 
and  ii.  in.  respectively,  mark  the  circles  about 
-j^  in.  larger,  so  that  the  guide  marks  will  not  be 
obliterated  in  machining.  Drill  the  sparking- 
plug  hole  |  in.,  to  be  ultimately  tapped  out  J-i  in. 
with  seventeen  threads  to  the  inch  to  suit  the 
standard  pattern  De  Dion  plugs.  If  a  tap  to 
suit  this  size  and  thread  is  not  to  hand,  the 
cylinder  can  be  chucked  on  the  face-plate  and 
screw  cut  to  suit  the  sparking  plug,  but  it  must 
not  be  threaded  till  the  cylinder  is  bored,  as  the 
plain  f-in.  hole  will  be  required  for  a  bearing  and 
guide  for  the  boring  bar.  Face  off  the  cylinder 
top  to  a  thickness  of  f  in.  (see  Fig.  108).  Fig.  109 
is  a  half  plan  of  the  cylinder  head. 

Boring  the  Cylinder. — To  bore  the  cylinder, 
bolt  the  casting  truly  on  the  saddle  of  the  lathe. 
It  should  be  held  firmly  in  position  by  two  stout 
iron  straps  bent  to  the  radius  of  the  cylinder,  and 
the  casting  should  be  packed  up  to  the  correct 
height  of  the  centres.  See  that  everything  is 
quite  firm  and  the  lathe  properly  adjusted  before 
starting  to  bore,  as  on  the  accuracy  of  the  work 
on  this  part  depends  in  a  great  measure  the 
efficiency  of  the  engine.  Take  at  least  three  cuts 
through— four  will  be  better— the  finishing  cut 
being  a  mere  scrape.  The  finishing  cut  and  the 
cut  before  it  should  be  taken  right  through  with- 
out a  stop  from  start  to  finish,  or  a  true  bore  will 
not  be  obtained. 


MOTOR   FOR   ATTACHMENT   TO   BIOTCLE.     127 

Making  the  Borinc/  Bar. — The  cylinder  boring 
bar  should  be  made  from  li-in.  or  li-in.  mild 
steel  with  one  end  turned  down  f  in.  to  pass  far 
enough  through  the  hole  in  the  top  of  the  cylinder 
to  allow  the  cutter  to  go  to  the  top  of  the  cylinder 
bore.  This  -f-in.  part  of  the  bar  must  fit  the  hole 
accurately,  without  shake  from  end  to  end.  The 


Fig.  109.— Half  Plan  of  Light-weight  iviotor  Cylinder  Head. 

bar,  before  being  turned,  should  be  drilled  and 
countersunk  at  each  end  to  the  same  angle  as  the 
lathe  centres.  Two  cutters  should  be  made,  one 
for  roughing  and  one  for  finishing,  the  latter  to 
be  used  on  the  finishing  cut  only,  and  to  be  dead 
to  size — namely,  2^  in.  To  make  a  perfect  job  the 


bore  should  be  taken  to  about 


under  size 


and  reamed  out  by  hand  in  the  vice  with  a  dead 


128 


MOTOR    BICYCLE    BUILDING. 


parallel  2^-in.  reamer,  if  this  tool  is  already  in 
the  possession  of  the  worker.  It  will  be  an  ex- 
pensive tool  to  make  or  purchase,  and  would  not 
be  economical  unless  a  number  of  cylinders  are 
to  be  bored.  A  substitute  may  be  a  copper  or 
lead  lap  fed  with  flour  emery  and  oil,  but  every 
particle  of  emery  must  be  washed  from  the  work 
with  paraffin  or  petrol.  If  it  is  to  be  lapped  out 
the  cylinder  must  be  bored  to  within  the  merest 
shade  of  the  finished  size. 

Cylinder  Flange,  Shoulder,  and  Chamfer. — 
The  flange,  shoulder,  and  chamfer  on  the  mouth  of 
the  cylinder  may  now  be  machined.  The  work 
may  be  done  at  the  same  setting  as  the  boring, 


Fig.  110.— Exhaust  Valve  Guide. 

by  making  cutters  to  fit  the  cutter  bar,  or  it  may 
be  done  on  a  mandrel  between  the  lathe  centres. 
To  avoid  making  a  mandrel  the  cutter  bar  may  be 
used,  a  collar  being  turned  to  fit  tightly  on  the 
|-in.  part  of  the  bar,  and  the  outside  may  be 
turned  up  in  its  place  to  fit  the  bore  of  the  cylin- 
der. The  small  end  of  the  bar  can  then  be  slipped 
from  the  inside  through  the  f-in.  hole  and  driven 
with  a  carrier  on  this  end.  The  flange  should  be 
turned  up  true  on  both  sides  and  left  f  in.  thick, 
and  the  shoulder  should  be  turned  2jf  in.  to  fit 
tightly  the  recess  in  the  crank  chamber.  This  part 
should  be  a  shade  taper,  so  that  the  screws  which 
fasten  it  to  the  flange  on  the  crank  chamber  will 


MOTOR   FOR  ATTACHMENT   TO   BICYCLE.      129 

pull  it  up  tight.  The  diameter  of  the  flange 
should  be  exactly  the  same  as  that  of  the  crank- 
chamber  flange.  The  mouth  of  the  cylinder  should 
be  chamfered  out  as  shown  in  Fig.  108  in  order 
to  facilitate  the  insertion  of  the  piston  and  rings. 

Boring  Out  Valve  Chamber. — The  casting  must 
now  be  chucked  on  the  face-plate,  head  outwards, 
and  fastened  down  with  a  bolt  passing  right 
through  the  sparking-plug  hole,  or  held  down 
by  the  flange  with  dogs  or  clamps.  Get  the  dotted 
circle  round  the  inlet  valve  opening  quite  true, 
and  bore  out  and  screw  the  hole  for  the  exhaust- 
valve-guide  (Fig.  110),  -f-in.  Whitworth  thread, 
and  with  a  hook  tool  face  the  under  side  for  the 
valve  guide  to  bed  truly  against.  Next  bore  the 
opening  and  seating  for  the  exhaust  valve  to  the 
sizes  and  angle  shown  in  Fig.  108.  The  sides  of 
the  exhaust  chamber  should  be  cleared  up  with 
the  hook  tool.  The  opening  and  seating  for  the 
inlet  valve  may  now  be  machined,  and  the  top 
part  bored  out  and  screwed,  as  shown  in  Fig.  108. 
Face  up  the  opening  so  that  it  is  \±  in.  from  the 
top  of  the  valve  seating.  The  casting  must  not 
shift  during  these  operations,  as  it  is  impera- 
tive that  the  exhaust-valve  seating,  the  screwed 
f-in.  hole,  and  the  under  part  for  the  exhaust- 
valve  guide  be  absolutely  true  with  each  other, 
or  the  exhaust-valve  will  never  be  a  gas-tight  fit. 
It  is  well  to  rough  the  parts  first,  and  then  finally 
go  over  the  above-mentioned  parts  with  a  light 
finishing  cut  to  make  sure  they  are  true.  The 
seating  and  screwed  part  for  the  inlet  valve  must 
also  be  dead  true  with  each  other. 

Exhaust  Pipe  Opening. — The  opening  for  ex- 
haust pipe,  shown  in  the  half  plan  of  the  cylinder 
top  (Fig.  109),  should  now  be  bored  or  drilled 
out  and  tapped  1  in.,  with  twenty-six  threads  to 
the  inch.  As  it  is  rather  light,  take  care  not  to 
burst  this  part  in  tapping.  It  is  well  to  drill  it 
out  rather  full,  so  that  the  tap  works  freely  ;  a 
I 


130  MOTOR    BICYCLE    KUILDING. 

full"  thread  is  not  necessary,  as  there  is  only  the 
weight  of  the  exhaust  silencer  for  it  to  support, 
and  this  has  a  long  bearing. 

Clearance  Holes  for  the  Holding-down  Pins. — 
Next  mark  off  the  bottom  of  the  cylinder  flange 
for  six  |-in.  clearance  holes  for  the  holding-down 
pins.  Start  the  first  hole  to  come  at  A  (Fig.  109), 
and  mark  off  the  other  five  equally  from  this. 
Get  the  holes  the  correct  distance  from  the  edge 
to  allow  the  screw  heads  to  clear  the  cylinder 
wall,  as  there  is  not  much  space.  The  best  form 
of  screw  for  the  purpose  has  a  square  head  with 
a  circular  collar  underneath. 

Exhaust  Valve  Guides. — The  guide  for  the 
exhaust  valve  and  the  exhaust-valve  push-rod 
guide  are  shown  in  Figs.  110  and  111  respectively. 


Fig1.  111.— Exhaust  Push-rod  Guide. 

The  guide  shown  in  Fig.  110  can  be  turned  from 
i£  in.  or  1-in.  case-hardened  mild  steel,  or  from 
tool  steel  hardened  and  tempered,  or  a  pattern 
can  be  made  for  this  and  for  the  push-rod  guide, 
and  phosphor-bronze  castings  obtained.  Which- 
ever method  is  adopted  the  machining  will  be  the 
same.  Drill  the  hole  right  through,  a  shade  under 
\  in.,  and  reamer  it  out  to  size.  Turn  up  a  man- 
drel to  fit  the  hole  tightly,  and  finish  up  the  out- 
side between  the  lathe  centres.  The  shoulder  may 
be  left  round,  and  two  or  three  g-in.  tommy  holes 
drilled  in  it,  or  it  may  be  filed  up  hexagon ;  the 
latter  is  preferable,  as  it  can  then  be  screwed  up 
tighter  than  with  a  tommy  wrench.  The  push- 
rod  guide  can  be  made  in  a  similar  manner,  two 
flats  being  filed  on  the  base  by  which  to  screw  it 


MOTOR   FOR   ATTACHMENT  TO   BICYCLE.      181 


up.  To  ensure  the  valve  seating  being  true  with 
the  bore  of  the  guide,  a  cutter  bar  may  be  made 
of  f-in.  or  |-in.  mild  steel  with  a  leg  turned  down 
to  fit  the  i-in.  hole,  a  cutter  being  made  to  the  size 
and  shape  of  the  valve  opening  and  seating;  this 
can  be  worked  round  with  a  lathe  carrier  by 
hand,  and  will  make  a  true  job. 

Exhaust   Valve. — The  exhaust  valve  should  be 


Fig.  112. 


Fig.  113. 


Figs.  112  and  118.—  Exhaust  Valve. 

made  to  the  dimensions  given  in  Figs.  112  and  113. 
The  head  and  stem  are  separate  pieces  screwed 
together,  and  the  end  is  riveted  over.  The  stem 
is  a  piece  of  f-in.  mild  steel  having  at  one  end 
-y\  in.  of  any  convenient  thread,  the  head  being 
tapped  to  suit  and  countersunk.  The  stem  is 
screwed  in  up  to  a  shoulder  and  riveted  over. 
The  valve  should  now  be  truly  centred  at  each 
end  and  turned  to  the  sizes  given  in  Figs.  112 


132  MOTOR    BICYCLE    BUILDING:. 

and  113.  The  part  to  rest  on  the  seating  should 
not  be  much  more  than  ^  in.  wide,  and  of  an 
angle  corresponding  to  that  of  the  seating  in  the 
valve  chamber.  The  projection  and  saw-cut  on 
the  head  is  for  use  when  grinding  the  valve  to  its 
seating  with  a  screwdriver,  or,  better,  a  screw- 
driver held  in  a  brace.  The  valve  grinding  should 
be  done  with  flour  emery  and  oil,  and  may  be 
finished  off  with  powdered  pumice  and  oil  after 
all  traces  of  the  emery  have  been  washed  away. 
The  hole  in  the  tail  end  of  the  valve  stem  should 
be  drilled  ~-  in.  and  opened  out  to  a  slight  taper. 
It  is  for  the  pin  to  hold  the  valve  spring  up  to 
its  work.  It  may  be  y0^  in.  from  the  end,  but  the 
exact  position  will  depend  on  the  length  and 


r 


Fig.  114.— Inlec  Valve. 

strength  of  the  spring  used,  and  it  will  be  best 
to  leave  this  hole  till  the  valve  and  spring  are 
tied  in  their  places. 

Inlet  Valve. — With  the  simple  form  of  car- 
burettor described  on  p.  99  the  inlet  valve  will 
be  part  of  the  carburettor,  but  should  it  be  de- 
sired to  fit  any  other  form  of  spray  or  surface 
type  carburettor,  then  the  inlet  valve  will  be  re- 
quired of  the  size  and  form  of  Fig.  114.  This 
should  be  as  light  as  possible  consistent  with  the 
work  it  has  to  do.  The  valve  body  (Figs.  115  and 
116)  is  an  iron  casting,  drilled  -•%  in.  and  turned 
to  size.  The  valve  must  be  ground  to  its  seating 
in  the  same  way  as  the  exhaust  valve. 

Inlet-Valve  Spring. — The  spring  for  this  valve 


MOTOR   FOR   ATTACHMENT   TO   BICYCLE.      133 

is  much  weaker  than  the  exhaust-valve  spring, 
as  the  valve  is  opened  by  the  suction  of  the  down- 
ward stroke  of  the  piston.  The  end  of  the  spring 
is  passed  through  the  hole  drilled  in  the  valve 
stem,  the  position  of  this  hole  being  left  till  the 
spring  is  tried  in  its  place.  It  is  best  to  buy 
these  valve  springs,  as  they  cost  only  a  few  pence 
and  are  then  certainly  of  a  suitable  strength. 
The  correct  adjustment  of  the  inlet-valve  spring 
is  a  very  important  matter,  and  can  only  be  ar- 
rived at  by  trial.  If  the  spring  is  too  strong  the 
valve  will  not  open  sufficiently  to  admit  a  full 


Figs.  115  and  116.— Body  of  Inlet  Valve. 

charge  of  gas,  and  if  too  weak  it  will  not  close 
quickly  enough,  and  will  thus  cause  loss  of  com- 
pression, and  possibly  back-firing. 

Drilling  Crank-Chamber  Flange. — The  cylin- 
der can  now  be  fitted  on  the  crank  chamber,  and 
the  holes  marked  off  to  correspond  with  the  six 
i-in.  holes  in  the  cylinder  flange.  Place  the  cylin- 
der on  the  crank  case  with  the  exhaust-valve  guide 
directly  over  the  centre  of  the  exhaust-cam  cham- 
ber on  the  crank  case.  Mark  off  through  the  holes 
in  the  cylinder  flange  with  a  scriber,  remove  the 
cylinder,  centre-dot  the  crank-chamber  flange- 
carefully,  drill  -Jg-  in.  bare,  and  tap  to  suit  pins 


134  MOTOR    BICYCLE    BUILDING. 

i-in.  Whitworth  threads,  using  paraffin  to  lubri- 
cate the  taps.  The  holes  must  be  tapped  care- 
fully, or  the  metal  will  tear  and  spoil  the 
thread.  Remove  the  tap  once  or  twice,  and  clear 
ott  the  dust  to  avoid  tearing.  Then  replace  the 
cylinder,  fasten  it  down  with  three  screws,  and 
with  a  long  drill  made  to  fit  the  bore  of  the 
exhaust-valve  guide,  drill  the  hole  in  the  cam 
chamber  for  the  push-rod  guide.  This  will  en- 
sure the  push-rod  being  exactly  in  line  with  the 
valve-stem.  Tap  it  ^-in.  Whitworth  to  suit  the 
.guide,  and  screw  it  in  place  and  test  for  truth. 
The  push-rod  will  be  a  short  length  of  steel  turned 
to  fit  the  guide  freely,  one  end,  operated  by  the- 
•cam,  being  rounded  and  hardened.  The  length 
must  be  arranged  so  that  with  TV  in.  between  the 
rod  and  the  valve  stem  the  valve  shuts  down  on 
its  seating. 

The  Piston. — The  piston  is  shown  in  section 
by  Fig.  117,  and  in  plan  by  Fig.  118.  The  hole 
for  the  gudgeon  pin  is  Ij  in.  from  the  front  of 
the  piston.  The  ring  grooves  are  ^  in.  wide  by 
g  in.  deep,  and  are  |  in.  apart.  The  distance 
apart  of  the  faces  of  the  bosses  for  the  gudgeon 
pin  is  l-g%  in. ;  this  is  Tj^  in.  more  than  the  length 
of  the  small  end  of  the  connecting-rod,  a  small 
amount  of  play  being  necessary  here  to  prevent  the 
piston  binding  in  the  cylinder.  Of  course,  the 
play  must  be  sideways  only,  the  fit  of  the  pin 
in  the  connecting-rod  bearing  simply  allowing  it 
to  work  quite  freely.  To  attain  a  high  speed 
with  the  least  possible  vibration,  the  piston,  and, 
in  fact,  all  reciprocating  parts,  such  as  the  con- 
necting-rod, should  be  as  light  as  is  possible  con- 
sistent with  strength.  Hold  the  piston  casting 
in  the  chuck  by  the  lug  cast  on  the  head,  and  turn 
up  the  outside  parallel  to  a  working  fit  in  the 
cylinder.  Take  a  very  fine  finishing  cut  with  a 
freshly  ground  tool  and  with  a  slow  feed.  When 
smoothed  off  with  a  very  fine  smooth  file,  the 


MOTOR   FOR   ATTACHMENT   TO   BICYCLE.      135 

piston  should  fit  the  cylinder  so  that  if  oiled  it 
will  sustain  its  own  weight.  True  up  the  bottom 
edge,  and  turn  a  very  narrow  groove,  -gV  in.  deep, 
T1^  in.  from  the  edge,  to  facilitate  lubrication. 
The  inside  should  be  turned  slightly  taper  as  far 
as  the  lugs,  as  shown,  the  thinnest  part  being  left 
y1^  in.  full  thick,  and  a  rim  should  be  left  on  the 
inside  J  in.  bare  thick,  this  strengthening  the 
edge  somewhat.  Face  up  the  head  to  the  lug  by 


Fig.  118. 


Fig.  117. 


Figs.  117  and  118.— Pisbon  of  Light-weight  Motor. 

which  the  casting  is  held,  leaving  this  part  J  in. 
thick.  Then  with  a  sharp-pointed  tool  mark  a 
light  line  round  the  centre,  as  a  guide  for  drilling 
the  gudgeon-pin  holes.  Then  carefully  turn  the 
grooves  for  piston  rings.  To  get  them  all  alike, 
make  a  tool,  similar  to  a  parting  tool,  just  -^  in. 
wide  and  well  backed  off  on  each  side  for  clear- 
ance. Any  burr  that  may  have  been  thrown  up 
should  be  carefully  smoothed  off,  and  the  head 


136  MOTOR    BICYCLE    BUILDING. 

parted  otf  with  a  long  parting  tool.  Smooth  off 
the  burr,  and  polish  the  head  with  several  grades 
of  emery  cloth.  The  more  highly  finished  the  head 
of  the  sylinder  the  better,  as  the  burnt  gases  will 
then  not  so  readily  accumulate  on»it.  If  it  is 
held  in  the  vice  for  polishing,  great  care  must 
be  taken  not  to  grip  the  thin  edge,  or  it  will  get 
cracked.  Mark  off  on  the  centre  line  the  positions 
of  the  pin  holes,  which  must  be  exactly  opposite 
each  other.  Drill  a  shade  under  the  size,  and  then 
hand-reamer  the  holes.  In  the  absence  of  a  reamer 
the  holes  should  be  drilled  with  a  twist  drill  to 
finish.  The  best  way  to  get  these  holes  true  is 
first  to  drill  halfway  on  tne  lathe  centre  with  a 
small  drill,  say  of  ^V  in-  diameter. 

Facing    Inside    Faces    of    Bosses. — The    inside 


Fig.  119. — Gudgeon  Pin  for  Piston. 

faces  of  the  bosses  must  now  be  tooled  with  a 
facing  cutter,  the  cutter  bar  fitting  the  hole  with- 
out shake.  The  cutter  is  fitted  to  the  bar,  turned 
up  in  place,  hardened,  and  let  down  to  a  light 
brown.  To  use  it,  pass  the  leg  of  the  bar  through 
tne  hole,  and  insert  the  cutter,  and  hold  the  cut- 
ter bar  in  the  chuck  with  the  back  centre  as 
support  and  feed  for  the  work.  Drill  a  j-in. 
clearance  hole  right  through  one  boss,  as  shown 
in  Fig.  118,  to  hold  the  pin  in  place.  One  hole  in 
each  lug  would  make  a  more  certain  job.  The 
face  of  the  hole  should  be  faced  for  the  head  of 
the  pin. 

Gudgeon  Pin. — The  gudgeon  pin  (Fig.  119) 
should  be  turned  from  i-in.  tool  steel ;  it  should 
be  quite  parallel,  and  fit  so  as  to  require  driving 
into  place  with  a  mallet.  Smooth  it  off  to  a  high 
finish,  knock  it  in  place,  and  through  the  hole  in 


MOTOR  FOR  ATTACHMENT   TO   BICYCLE.      137 

the  boss  drill  i-in.  tapping  size.  Remove  the  pin 
and  tap  i-in.  Whitworth,  smooth  off  the  burr,  and 
harden,  then  polish  and  let  down  to  a  brown  shade. 
Perhaps  the  easiest  way  to  ensure  the  tapped  hole 
coming  exactly  in  line  with  the  clearance  hole  is 
to  knock  the  pin  in  place  and  drill  to  tapping 
size  right  through,  then  remove  the  pin,  and  open 
out  the  holes  in  the  lug.  When  the  pin  is  in 
place  the  ends  should  be  clear  of  the  face  of 
the  piston ;  for  if  level,  or  projecting  in  the 
slightest,  the  hard  pin  will  mark  the  cylinder 
wnen  working.  The  screw  to  keep  the  pin  in 
place  may  have  a  cheese  head  with  a  screwdriver 
slot  or  a  square  head  with  a  round  collar  under, 
similar  to  those  used  to  fasten  the  cylinder  to 
the  crank  case.  The  latter  is  better,  as  the  pin 
should  be  a  very  tight  fit  to  avoid  any  possibility 


I  ./  \ 


Fi-r.  120.— Piston  Ring  Fig.  121.— Better  Form  of 

Joint.  Piston  Ring-  Joint. 

of  its  coming  loose  when  working,  but  a  box  key 
will  be  required  to  screw  it  up  with. 

Piston  Rings. — On  the  fit  of  these  rings  much 
depends,  ,as  if  they  are  not  perfectly  fitted,  loss 
of  compression,  and  consequently  loss  of  power, 
will  result.  There  are  several  ways  of  making 
these  rings,  and  the  subject  is  sufficiently  discussed 
in  Chapter  IV.  (see  pp.  57  to  59).  A  common 
method  in  cheap  motors  is  simply  to  bore  up  a 
cylindrical  casting,  turn  the  outside  to  finished 
size,  part  the  rings,  off  the  required  width,  and 
cut  them  through;  but  this  is  bad  practice,  as 
there  is  no  spring  in  the  rings  to  keep  them  up 
to  their  work  in  the  cylinder.  Make  four  rings 
whilst  on  the  job,  as  it  is  very  probable  that  one 
will  be  broken  in  finishing  or  springing  on  the 
piston,  and  even  if  not  it  is  well  to  have  a  spare 


138  MOTOR    BICYCLE    BUILDING. 

ring.  The  rings  should  now  be  cut  through  (see 
Figs.  120  and  121,  and  also  p.  37).  Before  the 
rings  are  cut  through,  they  should  be  tried  in 
the  piston  grooves,  and  should  go  to  the  bottom 
without  shake.  If  there  is  any  variation  in  the 
width  of  the  grooves,  number  the  rings  as  fitted. 
Should  the  rings  require  easing,  place  them  on  a 
flat  board  and  lightly  smooth  the  sides  with  a  very 
fine  smooth  file,  taking  care  to  keep  the  file  per- 
fectly flat.  Now,  when  the  rings  are  cut,  press 
the  joint  together  and  try  the  ring  in  the  groove, 
and  if  it  is  too  tight,  ease  a  little  off  the  insides 
of  the  joint.  They  should  be  without  shake,  but 
when  the  pressure  is  released  the  joint  will  spring 


Fig.  122.— Piston  Ring  Bored  Eccentrically. 

open.  With  the  rings  all  fitted  and  joints  made 
perfectly,  they  must  be  sprung  together  and 
turned  outside  to  2i  in.  in  diameter  to  fit  the 
cylinder  bore  (see  p.  126).  Before  removing  the 
rings  from  the  jig,  try  them  in  the  cylinder,  and 
if  they  are  a  smooth-working  fit  within  it  they  can 
be  removed  and  finally  bored  out  to  the  finished 
size,  2Li  in. ;  this  boring  will  be  eccentric  with 
the  outside,  as  shown  at  Fig.  122,  the  thick 
portion  measuring  ^  in.,  and  the  thin  part 
j\5-  in.,  being  at  the  joint.  The  rings  may 
be  held  so  that  all  are  bored  at  one  opera- 
tion. Make  a  band  clip,  about  J  in.  narrower 
than  the  combined  width  of  the  rings  to  be 


MOTOR   FOR  ATTACHMENT  TO   BICYCLE.      139 

bored,  of  sheet  steel  about  -^  in.  or  ^V  in.  thick ; 
clip  the  rings  with  the  joints  tight  together,  and 
hold  them  in  a  jaw  chuck.  The  rings  can  be  set 
true  by  the  part  of  the  ring  beyond  the  surface 
of  the  clip.  Bore  with  a  fine-pointed  sharp  bor- 
ing tool  with  a  very  light  cut  and  feed.  The 
rings  are  now  finished,  and  may  be  sprung  on  over 
the  head  of  the  piston  into  place.  This  has  to 
be  done  carefully,  or  a  fractured  ring  will  be  the 
result.  See  that  they  do  not  stick  in  any  part  of 
the  grooves;  if  they  do,  remove  and  carefully 
scrape  the  part  to  free  it.  With  careful  groov- 
ing and  fitting,  the  rings  should  just  drop  down 
tne  grooves  by  their  own  weight,  but  without  side 
shake. 

Connecting-rod.— -The  connecting-rod  (Figs.  123 
and  124)  can  now  be  machined.  Set  the  casting 
as  true  as  possible,  chuck  the  large  end,  and  bore 
it  out  |  in.  Chuck  the  small  end,  and  bore  it  f  in. 
In  chucking  the  small  end,  set  it  so  that  the  two 
bores  are  parallel  and  with  the  centres  5|  in. 
apart.  It  is  usual  in  doing  this  work  first  to 
mark  off  the  faces  of  the  bosses  on  a  level  surface 
with  a  scribing  block,  and  centre-dot  the  circles 
on  these  faces ;  but  with  the  special  set  of  castings 
designed  for  this  motor,  if  the  bosses  are  set  true 
with  the-  outsides,  the  bores  will  come  exactly 
5f  in.  apart  without  marking  off.  The  phosphor- 
bronze  bushes  for  the  two  ends  may  now  be  pre- 
pared. Chuck  the  large  one,  and  bore  and  reamer 
it  out  f  in.  The  small  bush  is  finished  -.?-  in.  in 
diameter.  Knock  each  bush  on  a  true  mandrel 
•of  the  proper  size,  and  turn  the  large  one  f  in. 
full  and  the  small  one  f  in.  full.  They  should  be 
a  very  tight  fit  for  their  respective  bores,  as  they 
are  to  be  shrunk  in  place.  Heat  the  boss  of  the 
'connecting-rod  to  about  the  heat  of  a  hot  solder- 
ing iron,  and  knock  the  bush  in  quickly  with  a 
mallet,  or  press  it  in  between  the  vice  jaws,  and 
•cool  at  once  in  cold  water.  If  this  is  properly 


140 


MOTOR    BICYCLE    BUILDING. 


done,  the  bushes  will  never  shift;  but  if  thought 
desirable,  or  if  the  bushes  are  found  to  be  not 
so  tight  a  fit  as"  was  intended,  a  hole  may  be 
drilled  half  in  the  bush  and  half  in  the  boss,  and 
a  small  screw  or  peg  may  be  driven  in,  and  cut 
off  Hush.  Now  face  off  the  sides  on  the  mandrel  in 
the  lathe  centres  to  the  dimensions  given  in 
t'ig.  123,  leaving  no  more  projecting  on  one  side 


Fi<r.  123.. 


Figs.  123  and  124. —Section  and  Elevation  of  Connecting-rod. 

than  on  the  other.  Two  oil  holes  should  be 
drilled  in  the  large  boss,  as  shown  at  A  (Figs.  123 
and  124),  and  well  countersunk.  To  facilitate 
lubrication,  file  a  small  groove  the  whole  length 
of  the  bushes  on  the  side  where  the  holes  pene- 
trate. 

Setting    Connecting-rod. — The    connecting-rod 
will  now  require  careful  setting.     The  mandrels 


MOTOR   FOR   ATTACHMENT  TO   BICYCLE.      141 

on  which  the  bushes  were  turned  should  be  in- 
serted in  the  ends,  and  tested  with  the  callipers 
to  see  whether  the  bores  are  parallel.  The  rod 
may  be  set  cold  if  found  out  of  truth.  These 
mandrels  should  be  made  rather  long,  say  6  in. 
or  7  in.,  as,  when  used  for  setting,  the  extra 


Fig.  125.— Shaft  and  Crank  of  Li<?ht-\veight  Motor. 

length  shows  up  any  irregularity  better.  The  bores 
of  the  bushes  should  certainly  be  reamered  out  to 
obtain  a  smooth  parallel  hole,  the  reamer  being 
finally  put  through  after  the  oil  holes  and 
grooves  have  been  drilled  and  filed. 

Main  Axle. — The  main  axle  should  be  made 
from  a  piece  of  tough  mild  steel,  case-hardened, 
or  of  hardened  tool  steel;  the  ends  should  be  let 


142  MOTOR    BICYCLE    BUILDING. 

down  rather  low,  however,  to  avoid  fracture, 
this  treatment  at  the  crank  disc  end  extending  to 
just  beyond  the  pinion  shoulder  (see  Fig.  125), 
and  at  the  fly-wheel  end  to  just  beyond  the  end  of 
the  keyway.  Let  these  parts  down  to  a  blue 
colour,  the  remainder  or  centre  portion  being  left 
brown.  A  tool  steel  axle  will  wear  longer  unless 
the  mild  steel  is  very  carefully  case-hardened. 
Cut  off  a  piece  of  steel  |  in.  or  f(}  in.  in  diameter 
and  5],}  in.  long.  Centre,  drill,  and  countersink 
each  end  to  the  same  angle  as  the  lathe  centres, 
and  turn  the  |-in.  part  to  fit  the  f-in.  reamered 
hole  in  the  crank-case  bush.  A  working  fit  with- 
out shake  is  needed.  If  the  axle  is  to  be  ground 
after  hardening,  leave  it  large  by  ^  in.  bare  for 
this.  Grinding  is  decidedly  preferable,  as  a  per- 
fectly true  axle  will  result,  but  of  course  a  good 
job  can  be  made  of  it  without  grinding  if  a  fit  is 
made  before  it  is  hardened,  and  care  is  observed 
not  to  warp  it  in  the  hardening  process.  The  end 
for  the  flywheel  lock  nuts  may  now  be  turned  to 
f  in.  for  f  in.  up,  and  then  a  line  should  be 
marked  round  the  axle  with  a  fine-pointed  tool, 
1  in.  farther  up  or  If  in.  from  the  end.  Now  set 
the  slide-rest  to  turn  a  smooth  taper  that  will 
start  at  this  line  and  finish  exactly  at  the  end  of 
the  f-in.  part.  Reverse  the  carrier  and  turn  down 
the  other  end  f  in.  f  in.  up. 

Securing  Crank  Disc  and  Flywheel. — The 
method  of  fastening  the  crank  disc  must  now  be 
decided.  The  plan  shown  in  Fig.  125  is  to  make 
the  axle  end  a  driving  fit  through  the  small 
pinion  and  crank  disc,  countersink  the  outer  side 
of  the  f-in.  hole,  and  rivet  the  axle  end  up  after 
a  key  or  grub  screw  has  been  fitted  right  through 
the  disc  and  pinion,  half  in  the  axle  and  half  in 
the  disc  and  pinion.  If  this  is  well  done  it  will 
make  a  firm  job,  but  for  preference  the  hole  in 
the  disc  and  pinion  should  be  tapped  out  f  in. 
by  twenty-six  threads,  and  the  axle  end  screwed 


MOTOR   FOR  ATTACHMENT  TO   BICYCLE.      143 

to  suit.  With  a  right-hand  thread  the  working  of 
the  engine  tends  to  screw  it  tighter,  though  if 
desirable  a  grub  screw  may  be  fitted,  but  then 
the  pinion  and  disc  must  be  screwed  right  home 
before  drilling  for  the  grub  screw.  The  other  end 
can  now  be  screwed  the  same  thread  for  the 
flywheel  lock  nuts.  The  keyway  for  the  flywheel 
should  be  sunk  1  in.  long  by  ^  in.  wide  by  J  in. 
deep,  but  if  this  cannot  be  cut  by  machine,  a 
parallel  keyway  filed  flat  will  be  best. 

Crank   Disc. — The   crank    disc   should   now   be 


Fig.  126.— Crank  Casting-. 

prepared.  Find  the  centre  of  the  axle  boss,  scribe 
a  line  centrally  on  the  crank-pin  end  of  the  disc, 
and  on  this  line  mark  off  and  centre-dot  exactly 
lj  in.  from  the  centre  of  the  disc  for  the  crank 
pin.  Scribe  a  guide  circle  round  these  centre 
marks  a  shade  larger  than  the  holes  to  be  drilled, 
and  centre-dot  these  circles  as  a  guide  for  drilling. 
If  a  true  drilling  machine  is  available,  these 
holes  may  be  drilled,  using  a  |-in.  or  T^-in.  drill 
first,  find  enlarging  to  the  finished  sizes,  which 
should  be  tapping  sizes  for  f  in.  by  twenty-six 


144  MOTOR    BICYCLE    BUILDING. 

threads,  left  hand,  respectively,  if  the  screwed 
method  of  holding  is  adopted.  In  any  case,  to 
facilitate  assembling,  the  crank  pin  should  be 
screwed  to  the  disc.  Then  tap  these  two  holes. 
The  crank  casting  is  shown  by  Fig.  126. 

Crank  Pin, — For  the  crank  pin,  cut  off  a 
length  of  If  in.  of  f-in.  steel,  and  centre,  drill, 
and  countersink  the  axle.  Regarding  the 
material,  the  same  remarks  apply  as  for  the 
main  axle.  Turn  this  up  f  in.  to  fit  the  large  end 
of  the  connecting-rod,  round  off  an  end,  and  turn 
down  the  other  end  to  %  in.  for  f  in.  up,  and  screw 
it  to  fit  very  tightly  the  tapped  hole  in  the  disc. 
This  must  be  a  left-hand  thread.  Provision  must 
be  made  for  screwing  this  home  after  the  main 
axle  and  disc  are  in  place  in  the  crank  case,  by 
filing  two  flats  on  the  outer  end  of  the  pin,  or 
drilling  a  J(-in.  hole  and  drifting  it  out  square 
for  a  key.  The  main  axle  and  crank  pin  may  now 
be  hardened.  Screw  the  pinion  and  crank  disc 
on  to  the  main  axle  the  reverse  way  to  the  final 
position,  that  is,  with  the  boss  outwards.  Face 
off  this  boss  true  in  the  lathe,  so  that  the  final 
combined  thickness  of  the  disc  and  boss  is  f  in., 
while  at  the  same  time  the  whole  of  the  boss  side 
of  the  disc  may  be  turned  up  and  the  other  boss 
for  the  crank  pin  faced  off.  Remove  the  disc  from 
the  axle,  screw  the  crank  pin  into  the  disc,  and 
turn  the  outer  side  of  the  disc.  If  the  edges  of 
the  disc  are  now  filed  up,  these  parts  will  be 
finished. 

Flywheel  and  Pulley. — The  flywheel  and  pulley 
are  in  one  casting  (see  Fig.  127).  Chuck  it  by 
bolting  to  the  face-plate,  or  by  a  three-  or  four- 
jawed  chuck  on  the  inside  of  the  rim.  Bore  out 
the  hole  to  the  taper  on  the  axle,  the  fit  being 
tested  with  red-lead  and  oil  smeared  on  the  axle 
end,  which  should  mark  the  hole  from  end  to  end 
and  all  round.  If  the  lathe  is  true,  the  axle  end 
may  be  finally  ground  in  with  fine  emery  and  oil. 


MOTOR  FOR  ATTACHMENT  TO   BICYCLE.      145 


The  edge  of  the  flywheel,  the  pulley  side,  and  the 
pulley  can  be  turned  at  this  chucking,  if  the  cast- 
ing is  held  in  a  jaw-chuck, 
or  it  can  be  roughed  at  this 
chucking,  and  finished  in 
its  place  on  the  main  axle, 
after  the  keyway  has  been 
cut,  the  key  fitted,  and 
nuts  are  screwed  home. 
The  latter  method  will  be 
more  likely  to  give  the 
truer  job.  This  key  must 
touch  on  both  sides  from 
end  to  end,  and  should  have 
a  slight  taper,  the  thicker 
end  being  towards  the  pul- 
ley side.  The  flywheel  is 
(S  in.  in  diameter,  with  a 
rim  li  in.  by  1|  in.  It 
may  be  lighter,  but  a 
heavy  wheel  gives  a 
steadier  running  motor. 
The  groove  A,  -^V  in.  deep 
by  £  in.  wide,  catches 
any  oil  which  may  leak 
out  of  the  axle  bearing, 
and  thus  prevents  it 
working  down  the  fly- 
wheel and  splashing  on 
to  the  rider.  The  pulley 
is  3j-  in.  in  diameter,  and 
the  belt  groove  is  -^  in. 
wide  at  the  top  by  g  in. 
at  the  bottom,  and  the 
flywheel  rim  will  require 
drilling  with  f-in.  or  J-in. 
holes  to  balance  the  pis- 
ton and  connecting-rod. 


Fig.  127.— Section  of  Fly- 
wheel and  Pulley. 


Gear  Wheels. — The  two  gear  wheels  to  work  the 
exhaust   and   ignition   cams   are   phosphor-bronze 
j 


HG 


MOTOR    BICYCLE    BUILDING. 


castings  having  thirty-two  and  sixteen  teeth 
respectively.  The  pinion  is  shown  in  section  in 
position  on  the  main  shaft  in  Fig.  125  (p.  141). 
The  larger  one  is  shown  in  section  on  the  exhaust 
cam  shaft  in  Fig.  128.  If  the  teeth  are  cast  they 
may  be  filed  to  shape  after  the  wheels  are  bored 
and  turned.  The  pinion  may  be  tapped  and 
screwed  on  its  shaft  and  turned  in  position.  Only 
just  true  the  top  of  the  teeth,  face  up  the  sides, 
and  scribe  a  fine  line  on  both  sides  as  a  guide 
for  filing  the  bottoms  of  the  teeth.  The  wheel 


1:50 


Fig.   12'J.  —  Exlaust 
Fig-.  128.— Exhaust^  Cam  Shaft.  Cam.     Fig-.  130.— 

Ignition  Cam. 

may  be  keyed  on  the  exhaust  cam  shaft  or  screwed 
on  with  a  J-g-in.  left-hand  fine  thread. 

Exhaust  Gam  Shaft. — The  exhaust  cam  shaft  is 
2|  in.  long  by  5  in.  in  diameter,  and  is  of  tool 
steel  for  preference,  hardened  and  let  down  to 
brown,  the  end  screwed  for  the  wheel  being  let 
down  to  a  blue  colour.  The  other  end  may  be 
turned  down  f  in.  for  -/^  in.  up  to  take  the  igni- 
tion cam,  which  may  be  fixed  by  drilling  a  V-^-in. 
or  3-Vin-  hole  right  through  both  cam  and  shaft 
while  a  small  split  pin  to  suit  is  passed  through; 
or  the  cam  and  the  end  of  the  shaft  may  be 
threaded  left-hand.  The  chief  consideration  in 
screwing  the  ignition  cam  is  the  difficulty  of 


MOTOR    FOR    ATTACHMENT    TO    BICYCLE.     147 

getting  it  right  home  to  the  shoulder  on  the  shaft 
so  that  the  cam  is  in  the  correct  position  for 
igniting;  for  this,  turn  a  shade  off  the  back  of 
the  cam  until  on  trial  it  is  found  to  come  in  the 
right  position.  Another  method  of  fixing  this 
cam  is  to  make  it  with  a  J-in.  square  hole,  filing 
the  end  of  the  shaft  to  suit,  and  allowing  the  end 
to  project  sufficiently  to  insert  a  small  split  pin. 
The  exhaust  cam  is  fixed  by  a  plain  flat  key. 

Exhaust  and  Ignition  Cams. — The  exhaust  and 
ignition  cams  (see  Figs.  129  and  130)  should  be 
turned  from  tool  steel  and  filed  or  milled.  The 
exact  shape  and  size  of  the  projection  qn  the 
exhaust  cam  cannot  be  decided  until  the  engine 
has  been  assembled  and  tested,  which  will  be 
explained  later  in  giving  particulars  of  timing. 
The  position  of  the  exhaust  cam  on  the  shaft  will 
be  determined  by  slipping  the  shaft  through  its 
bearing  in  the  crank  case,  with  the  thirty-two- 
tooth  wheel  screwed  up  tight.  The  cam  must  then 
come  right  up  against  the  face  of  the  bush  so  that 
there  is  no  endshake  to  the  shaft,  but  it  must 
revolve  freely.  After  the  timing  has  been  fixed, 
the  cams  should  be  hardened  and  let  down  to  a 
brown  colour.  The  ignition  cam  will  require 
hardening  only  on  the  projection. 

Timing  the  Exhaust  Valve. — For  this  purpose 
partly  assemble  the  motor  parts.  Connect  the 
piston  to  the  connecting-rod  by  the  gudgeon-pin. 
Screw  the  thirty-two-tooth  wheel  to  the  exhaust 
shaft,  place  this  in  position  in  the  crank  case,  key 
on  the  exhaust  cam,  put  on  the  cover  of  the  ex- 
haust cam  chamber,  and  place  the  main  shaft  in 
position  with  the  small  pinion  and  crank  disc 
attached.  Now  carefully  slip  the  cylinder  over 
the  piston  without  injuring  the  rings.  Fix  the 
cylinder  to  the  crank  case  by  two  screws,  and  slip 
the  crank  pin  through  the  large  end  of  the  con- 
necting-rod and  screw  it  into  the  crank  disc.  In- 
sert the  push  rod  into  its  guide,  and  put  the 


148  MOTOR    BICYCLE    BUILDING. 

exhaust  valve  with  spring  and  cotter  in  place. 
Before  going  further,  see  that  the  exhaust  stem 
is  of  such  a  length  that  there  is  ^  in.  play  be- 
tween its  end  and  the  top  of  the  push  rod  when 
the  valve  is  quite  shut  down  on  its  seating.  Now 
take  a  piece  of  ^-in.  or  TVin-  r°d  and,  placing  it 
through  the  sparking  plug  hole  in  the  top  of 
the  cylinder,  with  the  end  resting  on  the  top  of 
the  piston,  mark  off  on  the  rod  when  the  piston 
is  at  its  highest  and  lowest  positions.  The  wheels 
must  now  be  in  gear  so  that  when  the  main  shaft 
is  turned  forward  (the  way  the  engine  will  run) 
the  exhaust  valve  will  begin  to  open  f  in.  before 
the  piston  reaches  its  lowest  point,  and  will  shut 
exactly  at  the  moment  it  reaches  its  highest  point 
on  the  next  upstroke.  This  can  be  seen  by  watch- 
ing the  marks  on  the  rod  passed  through  the  top 
of  the  cylinder.  When  the  right  teeth  are  in  gear 
mark  them  with  a  centre  punch.  The  exhaust  cam 
must  be  filed  to  bring  it  into  the  correct  position. 
The  Ignition. — The  ignition  cam  may  now  be 
fitted  on  the  end  of  the  shaft  so  that  the  projection 
is  about  one  quarter  of  a  revolution  in  advance 
of  the  exhaust  cam.  The  advance  sparking  gear 
should  be  put  on  first;  then  the  ignition  cam 
should  be  so  placed  as  to  spark  when  the  piston 
has  |  in.  to  travel  to  complete  its  upward  com- 
pression stroke  for  the  earliest  or  most  advanced 
sparking,  and  so  that  the  spark  will  pass  after  the 
piston  has  descended  f  in.  for  the  latest  or  re- 
tarded sparking.  The  spark  will  pass  at  the  plug 
points  immediately  on  the  break  or  coming  apart 
of  the  platinum  points  of  the  trembler  blade  and 
screw.  On  the  frame  of  the  advance  sparking 
apparatus  and  the  edge  of  the  exhaust  cam  cham- 
ber mark  the  "  latest "  and  "  earliest  "  positions, 
as  guides  when  fitting  the  level  and  rod  to  work 
from  the  top  tube  of  the  bicycle.  The  advance 
sparking  apparatus  best  suited  to  this  motor  is 
the  small  one  of  Bassee  and  Michel. 


149 


CHAPTER    VIII. 

SPRAY    CARBURETTOR    FOR    LIGHT-WEIGHT    MOTOR. 

THIS  simple  and  efficient  carburettor,  shown  in 
section  and  elevation  by  Figs.  131  and  132,  is 
of  original  design,  and  has  been  made  and 
thoroughly  tested ;  it  would  suit  any  motor  of 
from  l^h.p.  to  2h.p.  It  is  fitted  with  a  throttle 
valve  and  an  extra  air  inlet,  which  have  been 
found  indispensable  for  successful  and  economical 
running.  In  fact,  it  is  very  difficult  to  keep  the 
cylinder  cool  without  these  additions.  For  the 
motor  described  in  the  previous  chapter  this  car- 
burettor will  be  specially  suitable.  With  it,  the 
petrol  tank  can  be  fitted  in  the  frame  or  behind 
the  saddle.  In  fitting  up  the  tank,  it  should  be 
borne  in  mind  that  the  bottom  must  be  above  the 
level  of  the  petrol  opening  at  the  needle  valve  of 
the  carburettor. 

No  special  tools  of  any  account  are  required 
to  make  the  carburettor,  a  small  lathe  of  3-in.  or 
4-in.  centres  being  all  that  is  necessary ;  and  if 
the  operator  is  handy  with  a  chaser,  it  need  not 
be  a  screw-cutting  lathe.  Should  the  screwed 
parts  which  connect  the  top  and  bottom  castings 
present  any  difficulty,  an  alternative  method 
would  be  to  make  the  screwed  part  a  plain,  tight, 
push  fit,  and  to  secure  with  three  or  four  small 
screws  put  through  the  edge. 

It  will  not  pay  to  make  the  patterns  unless 
several  are  to  be  made.  Six  of  these  are  required. 
Should  it  be  decided  to  make  them,  a  core-box 
for  the  main  body  pattern  will  be  necessary. 
Make  the  patterns  as  shown,  allowing  for  shrink- 
age and  machining. 


150 


MOTOR   BICYCLE   BUILDING. 


Chuck  the  main  body  casting  in  a  jaw  chuck, 
and  bore  out  the  inside  to  l£  in.  diameter  oip  to 
the  shoulder,  which  forms  the  valve  seating ; 
recess  out  the  end  1T^  in.  by  ^\  in.  deep.  Bore 
the  valve  seating  shoulder  Ij  in.  Face  off  the 
end,  and  turn  the  outside  of  the  bottom  flange. 
Turn  up  a  hardwood  stud  to  fit  the  inside  already 
bored,  knock  the  casting  on  true,  and  bore  out 
the  other  half  of  the  casting  l|  in.  Face  the  valve 


Fig.  132. 


Figs.  131  and  132.— Section  and  Elevation  of  Spray 
Carburettor  for  Light-weight  Motor. 

seating  true,  and  face  off  the  top  edge  ;  and,  if 
the  parts  are  to  be  screwed  together,  screw  at  this 
chucking  with  twenty-four  to  twenty-six  threads 
to  the  inch,  i  in.  down  the  casting.  Turn  up  the 
outside  of  the  flange  1-j-jv-  in.  If  the  lathe  is  not 
fitted  with  a  three-or-four-jaw  chuck,  the  casting 
may  be  knocked  on  a  hardwood  stud  for  the 
first  operation  as  well  as  for  the  second.  Chuck 
the  top  casting,  large  side  outwards,  bore  up  f  in. 
right  through,  turn  out  the  inside  of  the  large 


SPRAY    CARBURETTOR    FOR    MOTOR.        151 

part  If  in.  by  ^V  in.  deep,  and  screw  or  turn  the 
outside  to  fit  the  main  body  casting,  leaving  the 
edge  of  the  flange  the  same  size  as  the  flange  on 
the  main  body  casting — that  is,  1-y-in.  Turn  up 
the  remainder  on  a  f-in.  mandrel  between  the 
centres  to  the  dimensions  given. 

Drill  the  small  valve  stem  guide  A  (Fig.  133) 
im->  and  on  a  small  stud  running  in  the  chuck 
turn  up  the  small  recesses  shown  at  B  (Fig.  131) 
on  the  ends  to  fit  tight  in  the  f-in.  bore  of  the 
top  casting.  File  up,  and  solder  securely  in 
place.  Chuck  the  bottom  plate  casting  with  the 
long  end,  turn  the  edge  of  the  plate  to  fit  the 
recess  in  the  body  casting  tight,  and  turn  the 
sides  until  it  is  a  shade  thinner  than  the  depth  of 
the  recess  in  the  body  casting  ;  slightly  chamfer 
the  outside  edge  to  allow  of  the  edge  of  the  body 
casting  being  riveted  over  to  secure  the  bottom 
to  the  main  body.  Turn  the  short  -stem  to  f  in. 
diameter,  and  leave  it  i  in.  long;  drill  up  with 
a  small  drill  for  about  J  in.,  remove  from  the 
chuck,  and  turn  down  the  conical  end  f  in.  at  the 
base  by  f\-  in,  at  the  summit  by  f  in.  long.  While 
in  the  lathe,  mark  a  line  -—  in.  from  the  edge  for 
the  centre  of  the  holes  to  be  drilled  in  the  plate  ; 
these,  six  in  number,  are  T72-  in.  in  diameter. 

Knock  on  the  bottom  (but  do  not  rivet  it  over 
yet),  and  secure  the  top  part  to  the  body.  A  drill 
must  now  be  made  with  a  f-in.  shank,  and  the 
end  turned  down  and  formed  into  a  -jfVm-  drill. 
This  drill  will  be  4  in.  at  least  over  all,  but  the 
TfVin.  Part  should  be  kept  short-  to  avoid  spring, 
say  f  in.  The  hole  in  the  conical  part  of  the  bot- 
tom may  now  be  truly  started  by  passing  the  drill 
right  through  the  top  and  valve  stem  guide  while 
the  bottom  part  is  supported  on  the  back  centre. 
The  hole  will  be  f  in.  deep  of  this  size  ;  the  en- 
larged portions  can  be  drilled  on  the  centres  when 
taken  apart.  The  bottom  end  will  be  drilled  and 
tapped  to  suit  the  size  of  the  petrol  regulating 


152  MOTOR  BICYCLE  BUILDING. 

tap  used.  The  remainder  of  this  end  up  to  the 
^f-in.  hole  being  -/$  in.,  the  top  end  is  also  opened 
out  this  size  for  ^  in.  down.  This  may  appear  to 
be  an  elaborate  method  of  drilling  this  portion, 
but  it  is  quite  necessary,  as  it  must  be  perfectly 
true  with  the  valve  stem  guide  to  ensure  free  and 
proper  working  of  the  needle  valve. 

The  needle  valve  should  now  be  made.  The  stem 
should  be  turned  from  a  piece  of  iVin.  -steel.  The 
finished  size  is  Ij  in.  long  by  i  in.  at  the  screwed 
part,  the  end  being  turned  down  to  fit  loosely  the 
•aVin.  hole  in  the  top  of  the  conical  part,  termin- 
ating in  a  point  of  about  30° ;  the  side  of  this 
stem  where  it  enters  the  ^-in.  hole  should  have 
a  flat  filed  on  it  to  within  -Jg-  in.  of  the  point,  to 


Fig.  133.— Valve  Stem  Guide  of  Spray  Carburettor. 

allow  the  petrol  to  flow  by  freely.  The  plate  c 
(Fig.  131)  should  be  drilled  and  tapped  to  fit  the 
stem  tight,  a  small  lock-nut  fitted,  and  then  turned 
up  in  its  place,  lj  in.  diameter  by  about  /Tin. 
thick.  It  should  be  fixed  on  its  stem  in  such  a 
position  that  when  the  needle  valve  is  ground 
into  its  seat  the  plate  will  only  barely  touch  its 
seating — that  is,  the  plate  resting  on  its  seating 
must  not  prevent  the  needle  valve  closing  the 
petrol  inlet  thoroughly,  or  the  carburettor  will 
flood  and  work  irregularly.  A  saw-cut  should  be 
put  in  the  head  of  the  stem  for  a  screwdriver  to 
be  used  in  grinding  in  the  valve. 

The  throttle  valve  may  next  be  finished.     This 
is  shown  at  D  (Figs.  131,  132  and  134),  and  is  for 


SPRAY    CARBURETTOR    FOR    MOTOR.          153 

throttling  or  shutting  off  the  amount  of  gas  ad- 
mitted to  the  cylinder.  Drill  a  fVin.  h°le  through 
the  central  collar  E  (Fig.  132),  and  turn  up  the 
small  casting  D  (Fig.  134)  to  fit.  The  lever  and 
stem,  which  are  in  one  piece,  pass  through  the 
main  castings.  The  end  which  comes  through 
may  be  screwed  to  receive  a  small  nut  or  riveted 
over  to  secure  it.  The  D  section  part  of  the  stem 
which  passes  through  should  be  filed  so  that  the 
D  section  joins  the  round  exactly  at  the  sides  of 
the  f-in.  hole— that  is,  the  D  part  will  be  i  in. 
long.  A  |-in.  disc  of  sheet  brass,  about  No.  22 
gauge,  must  be  cut  out  truly  circular  to  fit  the 
bore  of  the  body  casting,  this  being  slipped  into 


Fig.  134. —Section  of  Carburettor  Throttle  Stem. 

place  and  secured  to  the  stem  by  soldering  or 
riveting.  It  must  allow  the  lever  to  work  freely, 
and  yet  close  the  f-in.  opening  when  shut.  It  is 
not  necessary  that  this  should  be  a  gas-tight  fit 
when  shut,  but  it  should  close  the  opening  effec- 
tively. 

When  the  lever  of  the  throttle  is  at  right  angles 
to  the  perpendicular,  the  disc  is  not  quite  shut, 
this  being  provided  for  when  filing  the  flat  on  the 
D  section  part  of  the  stem.  The  reason  for  this 
ig  that  correct  movement  of  the  operating  lever 
on  the  machine  is  facilitated  thereby.  The  end 
of  lever  D  is  drilled  with  a  §-in.  hole.  The  split 
lug  F  should  be  drilled  to  J-in.  tapping  size,  one- 
half  opened  out  to  J-in.  clearance  and  tapped  ^-in. 
Whitworth,  the  clearance  side  being  faced  level 
with  a  facing  cutter.  Saw  through  with  a  hack-saw 


154  MOTOE    BICYCLE    BUILDING. 

to  just  below  the  lug,  and  smooth  off  the  "fraze." 
The  extra  air  inlet  G  (Fig.  132)  should  be  drilled 
|  in.  and  faced  off.  The  cover  and  lever  should 
be  filed  up  and  drilled,  the  end  |  in.,  and  the  pivot 
hole  the  same  ;  it  should  be  placed  in  position  as 
shown,  and  the  position  of  the  hole  for  the  screw 
marked  off,  drilled,  and  tapped  to  suit  the  thread 
of  the  screw  used.  The  |-in.  opening  may  have 
a  very  fine  copper  gauze  disc  soldered  in  to  keep 
out  the  dust. 

The  wire  gauze  cone  H  (Fig.  131)  should  now 
be  marked  off  and  cut  out  as  in  Fig.  135,  bent 
to  shape,  soldered  together  at  the  edges,  and 
soldered  all  round  the  top  and  bottom  edges  to 


Fig.- 135.— Pattern  lor  Gauze  Cone.' 

the  carburettor  bottom  before  the  latter  is  finally 
riveted  in  place.  In  soldering  the  bottom  edge 
to  the  plate,  care  should  be  taken  not  to  allow  any 
solder  to  fall  on  the  part  which  rests  on  the  recess 
of  the  body,  or  it  will  not  bed  truly  thereon,  and 
therefore  the  central  hole  in  the  conical  part  will 
be  thrown  out  of  line  with  the  valve  stem  guide. 
A  very  light  spiral  spring  (not  shown)  will  be  re- 
quired, fitted  between  the  cross-bar  of  A  and  the 
top  of  the  valve  plate  c.  This  quickens  the  action, 
and  ensures  the  needle  valve  remaining  on  its 
seat  when  much  vibration  is  set  up.  The  carbu- 
rettor will  work  without  a  spring  in  ordinary 
circumstances,  but  it  is  better,  to  fit  one.  The 
strength  may  be  arrived  at  by  turning  the  carbu- 
rettor upside  down,  with  the  spring  in  place,  when 


SPRAY    CARBURETTOR   FOR   MOTOR.         155 

it  should  a  little  more  than  balance  the  weight 
of  the  valve. 

A  petrol  regulating  tap  should  be  fitted  to  the 
bottom  of  the  carburettor  by  screwing  in  with  a 
leather  washer  between,  to  make  a  petrol-tight 
joint.  This  tap  must  fit  well,  and  have  a  well- 
fitting  washer,  as  petrol  is  very  thin,  and  will 
work  its  way  through  the  smallest  aperture.  A 
suitable  tap  for  this  purpose  is  one  of  French 
make  of  2  millimetres  bore,  with  connecting  union. 
These  can  be  obtained  from  almost  any  factor  of 
motor  fittings. 


Fig.  136. — Induction  Pipe  and  Union  Nut. 

The  finish  may  be  left  in  the  brass,  polished, 
or  nickel-plated,  as  desired.  A  very  nice  finish 
may  be  obtained  by  having  the  body  part  dull- 
plated,  and  the  small  levers,  screws,  etc.,  plated 
and  polished. 

The  connecting  pipe  (Fig.  136)  will  be  a  piece 
of  1-in.  by  No.  16  gauge  steel  cycle  tube,  about 
9  in.  long,  bent  to  the  desired  shape.  One  end 
will  fit  into  the  top  of  the  carburettor,  being 
secured  by  tightening  the  pin  of  the  split  lug  on 
the  carburettor ;  to  the  other  end  is  brazed  a  steel 
washer,  li  in.  in  diameter,  with  |-in.  bore  and 


156 


MOTOR    BICYCLE    BUILDING. 


5  in.  thick.  This  must  be  faced  and  trued  up  on 
the  edges.  The  union  nut  (Fig.  137)  is  made  from 
a  brass  or  gunmetal  casting  to  the  dimensions 
and  shape  shown  in  Figs.  136  and  137.  The 
threaded  portion  is  lT"(i  in.  by  twenty  threads  to 
suit  the  "  Work "  motor,  and  the  flange  is  filed 
up  to  a  hexagon.  Besides  the  hexagon  for  screw- 
ing up,  it  is  advisable  to  drill  three  or  four  g-in. 
tommy  holes  in  the  top  portion,  so  that  if  a  large 
spanner  is  not  available,  a  punch,  or  even  a  large 


Fig.  137.— Plan  of  Union  Nut. 

nail,  may  be  used  to  undo  the  nut  should  occasion 
arise  on  the  road  to  have  to  take  this  off  for 
repairs  or  adjustment. 

A  hole  about  -—-  in.  diameter  should  be  drilled 
in  the  top  part  of  the  induction  pipe  as  near  over 
the  centre  of  the  inlet  valve  as  possible,  for  in- 
jecting paraffin  to  facilitate  easy  starting.  This 
hole  may  be  covered  with  a  small  spring  oil-hole 
cover,  as  used  on  bicycle  hubs.  The  section  of 
the  nut  in  Fig.  136  is  through  the  line  A  B 
(Fig.  137). 


INDEX. 


Advance    Sparkin 

122 

Air-release  Valve,  69 
Axle,  Bottom  Bracket,  37 
Back   Fork   Crown    Pattern 

20 
Ball-head,  Fitting,  42 

—   Pattern,   27,  28 
Ball-races,  Fitting,  36,  37 
Bearing  Bushes,  71 
Belt  Pulley,  Engine,  84-86 
Bobbin    for    Ignition    Coil,    10 

110 

Bolt  Holes  in  Crank  Case,  68 
Bolts  for  Crank  Case,  68 


-  ,  Engine,  Fitting, 
Boring  Bar  for  Cyl 
—   Cylinder,  47-52 


,  , 

for  Cylinder,  126 


Tube  Lugs,  32,  33 

Bottom  Bracket,  32 

Axle,  Fitting,  37,  38 

,  Brazing      Tubes      to, 

40-42 

Brazing       Tubes       to       Bottom 

Bracket,  40-42 
Bushes,  Engine,  71,  124 

in  Gear  Cover,  73 

—  for  Half-time  Shaft,  72 

•   of  Connecting-rod,  74-76 

,  Main-shaft,  72 

.  Tappet-rod,  73,  74 

Carburettor  Float-feed  Cham 
ber,  97,  98 

—  for  IJ-h.p.  Motor,  Making, 
149-156" 

• ,  Function  of,  97,  98 

• .  Spray,    for    3J-h.p.    Motor, 

,  Surface,  97 

Cam,  Exhaust,  87,  88 

Case,  Crank  (see  Crank  Case) 

Castings,  Building  Frame  from, 
32-46 

,  Frame,  Patterns  for,  16-31 

Chater  Lea's  Fittings  for  Tan- 
dem, 15 

Coil  Bobbin,  109,  110 

,  Compound  Primary,  with 

Trembler  Break,  107 

Condenser,  110,  111 

Connections,  115 

,  Ebonite  Shell  for,  108.  109 

for  3J-h.p.  Motor,  104-117 


Apparatus,  '  Coil,  Fitting,  to  Case,   116 

Insulation  of,  108,  109 

Heads  for.   105 
Primary,  104-107 

19,     Secondary,  109 

Trembler  for,  111-114 
Wire  for,  109 
Working  of,  116 
Condenser     for     Ignition    Coil, 

110,  111 
Connecting-rod  Bushes,  74-76 

•   for  IJ-h.p.  Motor,  139-141 

Contact-breaker,  90 
Core-boxes,  16 

,  Dowelling  Halves  of,  31 

|  Core-prints,  Painting,  30 
Cores,  Oval,  31 

,  Round,  30,  31 

Crank    Case    for    IJ-h.p.    Motor, 
120 

,  Attaching       Cylinder 

to,  69,  70 

,  Bolt  Holes  in, 

,  Bolting  up,  92 

•   Cover       for        IJ-h.p. 

Motor,  123,  124 

,  Cylinder   End   of, 

,  Fitting    Cylinder 

92,  93 

,  Machining,  65, 

,  Oil  Holes  in,  69 

Chamber  Flange,  Drilling, 

-   Disc  of  IJ-h.p.  Motor,  143, 

Crank  of  IJ-h.p.  Motor,  142 

—  Pin,  79,  144 

•  •   Lock-nut,  Safety  Lock 

for,  87 

Cranked  Tubes,  10 
Crown,  Back  Fork,   Fitting,  33 
,  ,  Pattern    for,    19, 

i  — ,  Front  Fork,  Fitting,  35 

i  — — ,  ,  Pattern  for,  27 

'•  Cylinder,  Boring,  47-52,  126,  127 

Bottom,  Flange  on,  53 

.   Castings  for  IJ-h.p.  Motor, 

End  of  Crank  Case,  66    6R 

,  Fitting  Crank  raS8  to,  92,  93 

—  Flange,  128,  129 


158 


MOTOR    BICYCLE     BUILDING. 


Cylinder,  Lapping  out,  56,  57 
Mouth,    Machining    Cham- 

Front Fork  Ends,   Pattern  for, 
23 

fer  at,  52 

Forks,  10 

of  IJ-h.p.  Motor,  126,  127 

—   Parts,  Fitting,  to  Rear,  43 

3J-h.p.    'Motor,     47-52, 
56,  69,  92 

Gauge  Numbers  of  Tubes,  14 
Gear  Cover,  Bush  in,  73 

to  Crank  Case,   Attaching, 

,  Engine,  11 

69,  70 

—   Wheel,    Keyway    in   Large, 

,  Turning  Outside  of,  53 

89 

Dowelling      Halves      of      Core- 

Wheels    of    IJ-h.p.    Motor, 

boxes,  31 

145 

Drilling  Girder  Tube  Stays,  34, 

3J-h.p.  Motor,  88, 

Driving,  System  of.  11 

Gear-case  Cover,  70 

Ebonite  Shell  for  Coil,  108,  109 

Gear-side  Main  Shaft,  80-81 

Engine,   Assembling,  91-93 

Girder  Tube  Lugs,  Pattern  for, 

Belt  Pulley,  84-86 

26 

•   Bolts,  Fitting,  39 

Stays,  Drilling,  34,  35 

Gear,  11 

Grinding  Valves,  63 

Lugs,   Fitting,  33 

Gudgeon  Pin,  82,  83 

,  Rear,  Pattern  for,  20, 

Hole  of  Piston,  54,  55 

21 

Half-time  Shaft,  81 

Plates,  Fitting,  36,  45 

,  Bush  for,  72 

,  Pattern    for,    29 

Handle-bar,    11 

,  Timing,  93,  94 

Head  Lugs,  Fitting,  34 

Exhaust  Cam,  87,  88 

,  Pattern  for,  24,  25 

Shaft,   146 

Ignition  Cams  for  IJ-h.p.  Motor, 

•   Bushing,  120,   121 

147,  148 

Pipe,  96 

—   Coils  (see  Coils) 

—   Opening,  53,  129,  130 

,  Timing,  94,  95,  147,  148 

Valve  Guide,  59,  60 

Induction  Pipe,  89,  90 

Lift,  74 

•  ,  Union  Nut  for,  76,  77 

Valves,  60-62,  129,  147,  148 

Inlet   Valve    for    IJ-h.p.    Motor, 

Eye,  Top  Stay,  22 

132,  133 

Flange  on  Cylinder  Bottom,  53 
,  Top,  121,  122 

-  —  •   for   3J-h.p.    Motor,    62, 
63 

Float-feed     Chamber     of     Car- 

Insulation    of     Ignition     Coils, 

burettor,  97,  98 

108,  109 

Flywheel  and  Pulley  for  IJ-h.p. 

Keywavs,     Cutting,    in    Shafts, 

Motor,  144,  145 

83,  "84 

Flywheels,  77-79 

Lapping  out  Cylinder,  56 

-—  ,  Balancing,  -92 

Leadbeater     and     Scott's    Axle 

Fork  Crown,   Back,  Fitting,  33 

Stamping,  37 

,  ,  Pattern    for,    19, 

"  Leave  "  on  Patterns,  29 

20 

Lock-nut,    Fitting,    to    Steering 

,  Front,  Fitting.  35 

Tube,  38 

—  ,  ,  Pattern    for,    26, 

,  Pinning,  to  Shaft,  87 

27 

Lugs,  Engine,  Fitting,  33 

Ends,  Front,  Fitting,  33,  34 

,  ,  Pattern    for,    20,    21 

,  ,  Pattern    for,    23, 

,  Fork,  19 

24 

.  Girder  Tube,   Pattern   for, 

,  Rear,  Pattern  for,  21, 

26 

22 

,  Head.  Fitting,  34 

,  ,  Setting,  40 

,  ,  Pattern  for,  24.  25 

•  Lugs,  19 
Forks,  Back,  10 

,  Lower  Horizontal,  Pattern 
for,  25,  26 

,  Front,  10,  43-45 

,  Seat,  Fitting,  34 

Frame,  9-15 

,  ,  Pattern  for,  25 

,  Building  up.  32-46 

,  Steering-tube,    Fitting,    35, 

•  Castings,       Patterns      for, 

36 

16-31 

,  ,  Pattern  for,  27 

,  Dimensions  of,  10,  11 

,  Tube.  Boring,  32,  33 

—  ,  Final  Setting  of,  46 

,  ,  Fitting,  34 

,  Forks  for,  10 

Main-shaft  Bushes,  72 

,  Tubes  for,  10                           ,  Gear-side,  80,  81 

INDEX. 


159 


Main-shaft  of  Motor,  79,  80 

Motor,  3i-h.p.:    Main  Shaft,  79, 

-,  Pulley  Side,  80 

80,  81 

Metal  Patterns,  31 

,  :  Piston,  53-59 

Motor,  li-h.p.,  118-148 

,  :  Rings,  57,  58 

,  :  Advance         Sparking 

,  :  Pulley,  80,  86 

Apparatus,  122 
,  :  Boring      out      Valve 

,  :  Silencer,  95,  96 
,  :  Tappet  Rod,  81,  82 

Chamber,  129 

,  :  Timing,  93,  94 

-,  :  Bushes,  124 

,  :  Union  Nut,  76 

,  :  Carburettor,  149-156 

-,  :  Valve  Seating,  52,  53 

,  .-  Connecting  Rod,   141 

,  :  Spring,  64 

,  .-  Crank  Case    120 
,  :  Disc,  143,  144 

,  —  :  Valves,  59-65 
Mud-guards,  11,  12 

,  :  •  Pin,   144 

Oil  Holes  in  Crank  Case,  69 

,  :  Cylinder  Boring  Bar, 
126 

Oil-pipe   Connection,    Hole    for, 
69 

,  :  Castings,  125-129 
,  •  :  Flange,  128,  129 

Painting  Core-prints,  30 
Paraffined     Paper,     Preparing, 

,  :  Drilling  Crank  Cham-           107,  108 

ber  Flange,  133 

Pattern  for  Back  Fork  Crown, 

,  :  Exhaust    Cam    Shaft, 

19,  20 

147                                                      Ball-head,  .27,  28 

,  :  and          Ignition    Bottom  Bracket,  16-19 

Cams,  146-148                                •  Engine  Plates.  29 

,  :  Pipe       Opening, 

—  -  Front  Fork  Crown,  26, 

129,  130 

27 

,  :  —  -  Push-rod   Guide, 

—  -  Ends,   23,  24 

130 

Girder  Tube  Lugs,  26 

,  :  Valve,  130-132 

_  Head  Lugs,  24,  25 

,  —  :  Flywheel  and  Pulley, 

-,  "  Leave  "  on,  30 

144,  145 

for      '  Lower       Horizontal 

,  :  Gear  Wheels,  145 

Lugs,  25,  26 

,  :  Gudgeon  Pin,  136 

,  Metal,  31 

,  :  Ignition,  149 

—   for  Rear  Engine  Lug,  20,  21 

,  :  Inlet  Valve,   132,   133 

•   Fork  Ends,  21,  22 

,  :  Main  Axle,  141 

•  Seat  Lug,  25 

,  :  Piston.  134-139 

Steering    Tube    Lugs, 

,  :  Shaft  and  Crank,  142 

27,  28 

,  :  Spray       Carburettor, 

•  Top  Stay  Eye,  22 
Patterns    for    Frame    Castings, 

,  :  Top  Flange,  121,   122 
,  :  Valve  Chamber    129 

16-31 
—  ,  Wood  for,  16 

,  3J-h.p.,  47-96 

Petrol  Vaporisation,   104 

,  •  :  Assembling,  91-93 

Pin,  Crank,  79,  80 

,  :  Boring    Cylinder,    47, 

,  Gudgeon,  82,  83' 
Pipe,  Exhaust,  Opening  for,  53 

,  :  Bushes,  71-76 

,  Induction  or  Inlet,  89.  90 

,      :      Connecting   -   rod 
Bushes,  74-76 

Piston  of  IJ-h.p.  Motor,  134-139 
,  Gudgeon  Pin  for,  136 

,  :  Contact  Breaker,  90 

,  Ring  Grooves  in,  54 

,  :  Crank  Pin,  79 

Rings,  57-59,  137-139 

,  :  Crank-case,  65-70 

of  34-h.p.  Motor,  53-59 

,  •:  Exhaust  Cam,  87,  88 

,  Gudgeon-pin  Hole  of,  54,  55 

,  •  :  •   Valve    59-62 

Plates,  Engine,  Fitting,  45 

-,  :  —     Guide.  57 

.  ,  Pattern  for,  29 

,  :   Lift,  74 

Pulley,  Belt,  84-86 

,  •  :  •  Spring    63 

•,  Securing,  to  Shaft,  86,  87 

,  :  Flywheels,    77-79 

Side  Main  Shaft,  80 

,  :  Gear-case  Cover,  70 

Rear   Fork   Ends,    Pattern   for, 

,  :  Gear  Wheels,  88,  89 

21,  22 

,  :  Gudgeon  Pin,  82,  83 

Ring  Grooves  in  Piston,  54 

,  :  Half-time  Shaft,  81 

Rings,  Piston,  57-59 

.  :  Induction     Pipe,     76, 

Rod,   Tappet,  81,  82 

77,  89,  90 

Seat  Lug,  Fitting,  34 

—  -,  :  Inlet  Valve,  62,  63 

—  -  —  Pattern,  25 

160 


MOTOR    BICYCLE    BUILDING. 


Shaft,  Half-time,  81 
,  Main,     79,     80     (see    Main 

Tube  Stays,  Drilling  Girder,  34, 

Shaft) 
,  Pinning  Lock-:iut  to,  87 

Tubes,      Brazing,      to      Bottom 
Bracket,  40-42 

,  Securing  Pulley  to,  86,  87 
Shafts,  Cutting  Keyways  in,  83, 

,  Cranked,  10 
,  Gauge  Numbers  of,  14 

84 

,  Main-frame,  10 

Silencer,  95,  96 

,  Sizes  of,  14 

,  Exhaust  Pipe  for,  96 

•   for  Tandem,  15 

Spray    Carburettor    for    IJ-h.p. 

Union  Nut  for  Induction  Pipe, 

Motor,  149-156 

76,  77 

3J-h.p.  Motor,  98- 

Valve.  Air-release,  69 

103 

Chamber,  Boring  out,  129 

Springs,  Valve,  64 

—  —  ,  Exhaust,  for  IJ-h.p.  Motor, 

Stay  Eye,  Top,  Pattern  for,  22 

130-132 

Stays,  Back,  10 

,  •   for  3J-h.p.   Motor,   60- 

,  Top  Back,  Fitting,  43 

62 

Steering  Tube,  Fitting  Lock-nut 

,  —  ,  Lift  of,  74 

to,  38,  39 

,  ,  Timing,  147,  148 

Lug   Casting,    Fitting, 

,  Inlet,     for    IJ-h.p.    Motor, 

35,  36 

132,  133 

,  Pattern  for,  27 

—  ,  ,  for  3J-h.p.   Motor,   62, 

Surface  Carburettor,  97 

63 

Tandem,  Tubes  for,  15 

Seating,  52,  53 

.  Chater  Lea's  Fittings  for, 

Springs,  63,  64 

15 

Stems  Breaking,  64,  65 

Tappet  Rod,  81,  82 

Valves,  Grinding,  63 

Bush,  73 

Waste-oil  Outlet,   69 

Throttle  Valve,  152,  153                    Wheel  Base,  14 

Timing  Engine    93.  94                        Wheels,  Gear,  88.  89,  145 

Exhaust  Valve,  147,  148            ,  •  ,  Keyway  in  Large    89 

-    Ignition,  94,  95,  148                   ,  Road.  Size  of,  11 

Trembler  for  Ignition  Coil,  111-    Wire   for  Ignition   Coil,   109 
114                                                     Wood  for  Patterns.  16 

Tube  Lugs,  Boring.  32,  33 

Working  Drawings,  Preparation 

-    ,  Fitting,  34 

of,  12,  14 

PRINTED  BY  CASSELL  &  COMPANY,  LIMITED,  LUDOATF.  HILL,  LONDON,  E.G. 


HANDICRAFT   SJS-RJgS    (continued). 

Electro-  Plating.     With  Numerous  Engravings  and  Diagrams. 

Contents. — introduction.  Tanks,  Vats,  and  other  Apparatus.  Batteries, 
Dynamos,  and  Electrical  Accessories.  Appliances  for  Preparing  and  Finishing 
Work.  Silver-Plating,  Copper-Plating.  Gold-Plating.  Nickel  Plating  and 
Cycle-Plating.  Finishing  Electro-Plated  Goods.  Electro-Plating  with  Various 
Metals  and  Alloys.  Index. 

Clay  Modelling  and  Plaster  Casting.    With  153  Engravings  and 

.Diagrams. 

Contents.— Introduction.  Drawing  for  Modellers.  Tools  and  Material  for 
Modelling.  Clay  Modelling  Modelling  Ornament.  Modelling  the  Human 
Figure.  Waste-moulding  Process  for  Plaster  Casting.  Piece-moulding  and 
Gelatine  Moulding.  Taking  Casts  from  Nature.  Clay  Squeezing  or  Clay 
Moulding.  Finishing  Plaster  Casts.  Picture  Frame  in  Plaster.  Index. 

Violins  and  Other  Stringed  Instruments.    With  about  180 

Illustrations 

&«/«»/*.— Materials  and  Tools  for  Violin  Making.  Violin  Moulds.  Violin 
Making.  Varnishing  and  Finishing  Violins.  Double  Bass  and  a  Violoncello. 
Japanese  One  string  Violin  Mandolin  Making.  Guitar  Making.  Banjo 
Making.  Zither  Making  Dulcimer  Making.  Index. 

Glass  Writing,  Embossing,  and  Fascia  Work,    (including 

the  Making  '.d  r  ixing  of  Wood  Letters  and  Illuminated  Signs.)     With 
129  Illustrations. 

Contents.— Plain  Lettering  and  Dimple  Tablets.  Gold  Lettering.  Blocked 
Letters.  Ste-cil  Cutting.  Gold  Etching.  Embossing.  French  or  Treble 
Embossing.  Incised  Fascias,  Stall-plates,  and  Grained  Background.  Letters 
in  Perspective;  Spacing  Letters.  Arrangement  of  Wording  and  Colors.  Wood 
Letters  Illuminated  Signs.  Temporary  Signs  for  Windows.  Imitation 
Inlaid  Signs.  Imitation  Mosaic  Signs.  Specimen  Alphabets.  Index. 

Photographic  Chemistry.     With  31  Engravings  and  Diagrams. 

Contents. — Introductory  :  Relation  of  Chemistry  to  Photography.  Some 
Fundamental  Chemical  Laws.  Meaning  of  Symbols  and  Equations.  Water: 
its  Properties  and  Impurities.  Oxygen  and  Hydrogen  Photographically  Con- 
sidered. Theories  Concerning  the  Latent  Image.  Chemistry  of  Development, 
Toning,  Intensification,  etc.  Nitrogen  Compounds  Employed  in  Photography. 
The  Halogens  and  Haloid  Salts.  Sulphur  and  its  Compounds.  Metals,  Alkali 
Metals,  etc.  Organic  or  Carbon  Compounds  used  in  Photography.  Pyroxyline, 
Albumen,  Gelatine,  etc.  Benzene  and  the  Organic  Developers.  Index. 

Photographic  Studios  and  Dark  Rooms.     With  180  Illus- 
trations. 

Contents.— Planning  Studios.  Building  Studios.  Portable  and  Temporary 
Studios.  Studios  Improvised  from  Greenhouses,  Dwelling  Rooms,  etc. 
Lighting  of  Studios.  Backgrounds.  Scenic  Accessories.  Dark-Rooms.  Portable 
Dark-Rooms.  Dark-Room  Fittings.  Portable  Dark  Tent.  Index. 

Motor   Bicycle   Building.     With  137  Illustrations  and  Diagrams. 

Contents. — Frame  for  Motor  Bicycle.  Patterns  for  Frame  Castings.  Build- 
ing Frame  from  Castings.  Making  3i  H.  P.  Petrol  Motor.  Spray  Carburettor 
for  si  H.  P.  Motor.  Ignition  Coils  for  Motor  Cycles.  Light-weight  Petrol 
Motor  for  Attachment  to  Roadster  Bicycle.  Spray  Carburettor  for  Light- 
weight Motor.  Index. 

Other  Volumes  in  Preparation. 


DAVID  McKAY  Publisher,  610  South  Washington  Square,  Philadelphia. 


This  book  is  ni  IE  ~*  •«— ' 


Return  this  material  to  the  library 
from  which  it  was  borrowed. 


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THE  LIBRARY 

UNIVERSITY  OF  CALIFORNIA 
LOS  ANGELES 


TECHNICAL 


Practical  Handrailini 

Contents. — Principles  of  hi 
Drawing,  Simple  Handrails. 
The  Uses  of  Models  Obtain 
Construction  and  Use.  Twi: 
Orthogonal  or  Right-angle  Sy: 
for  Stone  Stairs.  Setting  ou  •• 

Caps.     Intersecting  Handrails 

Practical  BrtckWork.    With  368  niu 

and   Flemish   Bonds. 


Bonds  for 


Angles.     Excavations,  Foundations,  and  F< 


000  882431 


ations. 

ion  of  Terms.  Geometrical 
s  on  the  Cylindrical  System, 
evels.  Face  Moulds  :  their 
Completing  the  Handrail, 
ithed  Handrails.  Handrails 
•ails.  Setting  out  Moulded 
,.  Index.  ^ 

Garden  and   Boundary   Walls. 


unctior 


atings.   Jum 

of  Cross   Walls.     Reveals,    Piers.     Angles   and  other   Bonds.     Jointing  and 
Pointing.     Damp-proof  Courses  and  Construction.     Hollow  or  Cavity  Walls. 
Chimneys  and  Fireplaces.     Gauged  Work  and  Arches.     Niches  and  Domes. 
Oriel  Windows. 
Practical  Painters'  Work.     With  Numerous  Illustrations. 

Contents.— Objects,  Principles  and  Processes  of  Painting.  Painters'  Tools 
and  Appliances.  Materials  used  by  Painters.-  Preparing  Suifaces  for  Paint- 
ing, Painting  Woodwork,  Painting  Ironwork,  Painting  Stucco  or  Plaster: 
Distempering  and  Whitewashing  Color  Combination.  House  Painting.  Varnish 
and  Varnishing.  Stains  and  Stafnirig.  Estimating  and  Measuring  Painters' 
Work.  Index.  *^ 


Textile    Fabrics   and    Their    Preparation   for    Dyeing. 

With  Numerous  Illustrations. 

Contents.—  Cotton.  Flax,  Jute,  and"  China  Grass.  Wool.  Silk.  Cotton 
Bleaching.  Linen  Bleaching.  Mercerising.  Wool  Scouring  and  Bleaching, 
Scouring  and  Bleaching  Silk.  Water.  About  Dyeing.  Index. 

Coloring    Matters   for    Dyeing    Textiles.     With  Numerous 

Illustrations. 

Contents.  —  Indigo  Coloring  Matters.  Logwood  Coloring  Matters.  Natural 
Red  and  Yellow  Coloring  Matters.  Aniline  Coloring  Matters.  Azo  Coloring 
Matters.  Anthracene  Coloring  Matters.  Chrome  Yellow,  Iron  Buff,  Man- 


ganese Brown,  Prussian   Blue,  Method   of   Devising  Experiments  in  Dyeing. 
of  the  Value  of  Coloring  Matters.     Index. 


Estimation 


Sanitary  Construction  in  Building.    Wit 

Contents.— Introductory.     Soils,  Subsoils,  and  Sites.     A 


With  131  Illustrations. 

Materials  of  Construc- 
tion. Footings,  Foundations,  and  Damp-proof  Courses.  Stability  of  Walls. 
Roofs.  Floors,  Hearths,  and  Staircases.  Air  Space  and  Ventilation.  A 
Typical  Dwelling.  Index. 

Iron:   Its  Sources,  Properties,  and  Manufacture.    With 

Numerous  Illustrations. 

Contents.— Introductory;  Terms  Explained.  Refractory  Materials,  Crucibles, 
etc.  Ores  of  Iron.  Metallurgical  Chemistry  of  Iron.  Cast  Iron  or  Pig  Iron. 
Preparation  of  the  Ores.  Changes  in  the  Blast  Furnace.  Blast  Furnace. 
Air  Supply.  Blowing  Engines  Working  the  Blast  Furnace.  By-products. 
Malleable  or  Wrought  Iron.  .  Production  of  Malleable  Iron.  Preparation  of 
Malleable  Iron  in  Open  Hearths.  Puddling.  Refining  Pig  Iron  and  Dry 
Puddling.  Forge  Machinery.  Iron-rolling  Mill.  Index. 

Other  New  Volumes  in  Preparation. 


DAVID  McKAY,  Publisher,  610  South  Washington  Square,  Philadelphia. 


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